SAN FRANCISCO (AP) -- Groundwater losses from the Colorado River basin appear massive enough to challenge long-term water supplies for the seven states and parts of Mexico that it serves, according to a new study released Thursday that used NASA satellites.

Researchers from NASA and the University of California, Irvine say their study is the first to quantify how much groundwater people in the West are using during the region's current drought.

Stephanie Castle, the study's lead author and a water resource specialist at the University of California, Irvine, called the extent of the groundwater depletion "shocking."

"We didn't realize the magnitude of how much water we actually depleted" in the West, Castle said.

Since 2004, researchers said, the Colorado River basin — the largest in the Southwest — has lost 53 million acre feet, or 17 trillion gallons, of water. That's enough to supply more than 50 million households for a year, or nearly fill Lake Mead — the nation's largest water reservoir — twice.

Three-fourths of those losses were groundwater, the study found.

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Sprinklers water a lawn Tuesday morning, July 15, 2014, in Sacramento, Calif. In an effo …

Unlike reservoirs and other above-ground water, groundwater sources can become so depleted that they may never refill, Castle said. For California and other western states, the groundwater depletion is drawing down the reserves that protect consumers, farmers and ecosystems in times of drought.

"What happens if it isn't there?" Castle said during a phone interview. "That's the scary part of this analysis."

The NASA and University of California research used monthly gravity data to measure changes in water mass in the basin from December 2004 to November of last year, and used that data to track groundwater depletion.

"Combined with declining snowpack and population growth, this will likely threaten the long-term ability of the basin to meet its water-allocation commitments to the seven basin states and to Mexico, Jay Famiglietti, senior author on the study and senior water-cycle specialist at NASA's Jet Propulsion Laboratory, said in a statement.

The Colorado River basin supplies water to about 40 million people and 4 million acres of farmland in seven states — California, Arizona, Colorado, New Mexico, Nevada, Utah and Wyoming — as well as to people and farms in part of Mexico.

California, one of the nation's largest agricultural producers, is three years into drought. While the state has curtailed use of surface water, the state lacks a statewide system for regulating — or even measuring — groundwater.

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Israel kills senior Gaza militant, mulls next move

Smoke from an Israeli strike rises over the Gaza Strip, Friday, July 25, 2014. An Israeli defense official says the Israeli Security Cabinet is meeting to discuss international ceasefire efforts, but also the option of expanding its eight-day-old ground operation in Gaza. (AP Photo/Lefteris Pitarakis)

JERUSALEM (AP) — Israeli aircraft struck 30 houses in the Gaza Strip early Friday, killing a leader of the militant Islamic Jihad group and two of his sons, as Israel's Security Cabinet was to decide whether to expand its operation or consider ideas for a cease-fire.

Israeli ground troops and Hamas gunmen fought intense battles in the north and center of the territory, Palestinian officials said.

The Israeli military said it hit 45 sites in Gaza, including what it said was a Hamas military command post, while Gaza militants continued to fire dozens of rockets at Israel, with one hitting an empty house.

On the 18th day of fighting, Israel's Security Cabinet was to convene later Friday to consider international cease-fire proposals, an Israeli defense official said, speaking on condition of anonymity because the deliberations were taking place behind closed doors.

One plan calls for a five-day humanitarian truce during which Israel and Hamas would negotiate new border arrangements for blockaded Gaza, said Hana Amireh, a senior Palestine Liberation Organization official in the West Bank, who is involved in cease-fire efforts.

Hamas has said it will not halt fire without international guarantees that Egypt and Israel will open Gaza's border crossings and end their seven-year-old blockade. Israel and Egypt are reluctant to ease the blockade, fearing this will enable Hamas to tighten its grip on Gaza.

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Palestinian boys stand next to wall with murals and Arabic writing that reads "Tiba standard nursery …

Israeli government spokesman Mark Regev said Hamas chief Khaled Mashaal has "put so many preconditions on a cease-fire so as to make it impossible."

Israeli media reported that the military also wants more time to continue destroying rocket sites and tunnels from Gaza into Israel, which Hamas has used to launch attacks. The military says it has found 31 tunnels but only destroyed about one-third of them so far. Israel has mobilized over 65,000 reserve forces during the fighting.

In Jerusalem, hundreds of Palestinians protested in the traditionally Arab east of the city after Muslim noon prayers, and a dozen protesters threw rocks and fireworks at Israeli police, who fired stun grenades and water cannons. Thousands of Israeli security forces had been deployed for possible Palestinian protests.

The night before, thousands of Palestinians protesting the Gaza fighting clashed with Israeli security forces in the West Bank and in east Jerusalem in one of the biggest protests in the territory in years. One Palestinian was killed and dozens were wounded, according to Palestinian medical officials.

In Gaza, the Palestinian death toll reached 828, after 115 were killed on Thursday in one of the deadliest days of fighting, said Ashraf al-Kidra, a Palestinian health official. More than 5,200 Palestinians have been wounded since July 8, he said.

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Israeli tank rides near the Israel and Gaza border Friday, July 25, 2014. Early Friday, Israeli warp …

During the same period, 35 Israelis, among them 33 soldiers, and a Thai worker were killed. Included in the count is an Israeli reservist killed Friday, the army said.

Early Friday, Israeli warplanes struck 30 houses throughout the Gaza Strip, including the home of Salah Hassanein, a leader of the military wing of Islamic Jihad, the second-largest militant group in Gaza after Hamas.

Hassanein and two of his sons were killed in the airstrike, said Gaza police spokesman Ayman Batniji and al-Kidra. The Israeli army confirmed the strike.

Over the past two weeks, Israeli aircraft have repeatedly hit homes of Hamas and Islamic Jihad leaders. Most had gone into hiding, but the strikes killed a leader of an Islamic Jihad rocket squad, a Hamas commander and a son of senior Hamas leader Khalil al-Haya, according to the Israeli military.

Such strikes have also claimed the lives of a large number of civilians. A Gaza human rights group said earlier this week that close to 500 homes have been damaged or destroyed in direct hits from the air, and that more than 320 people have been killed in their homes as a result of military strikes.

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A Palestinian man walks next to a destroyed house following an overnight Israeli strike in Gaza City …

Germany's two largest airlines said they are not yet resuming flights to Israel even though the European Aviation Safety Agency has lifted a recommendation that airlines refrain from flying to Tel Aviv.

Air Berlin says flights to Tel Aviv remain suspended at least through midday Friday, while Lufthansa says all Friday flights to the airport have been canceled because of ongoing security concerns after a Gaza rocket landed about a mile away from Israel's international airport.

Lufthansa's cancellations apply to subsidiaries Germanwings, Austrian Airlines, Swiss and Brussels Airlines as well.

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Barzak reported from Gaza City. Associated Press writer Karin Laub in Gaza City, Gaza Strip contributed to this report.

By Nidal al-Mughrabi and Dan Williams

GAZA/JERUSALEM (Reuters) - U.S. Secretary of State John Kerry pressed regional leaders to nail down a Gaza ceasefire on Friday as the civilian death toll soared, and further violence flared between Israelis and Palestinians in the occupied West Bank and Jerusalem.

Mediators hope any truce in the Gaza Strip can coincide with a Muslim festival that starts next week, and are looking to overcome seemingly irreconcilable demands from Israel and Hamas-led Islamist fighters, locked in conflict since July 8.

As the diplomacy continued, so did the fighting.

Gaza officials said Israeli strikes killed 33 people on Friday, including the head of media operations for Hamas ally Islamic Jihad and his son. They put the number of Palestinian deaths in 18 days of conflict at 822, most of them civilians.

Militants fired a barrage of rockets out of Gaza, triggering sirens across much of southern and central Israel, including at the country's main airport. No injuries were reported, with the Iron Dome interceptor system knocking out many of the missiles.

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Israeli APCs drive near the Israeli border with Gaza as the come out of the Gaza Strip July 25, 2014 …

The Gaza turmoil stoked tensions in the nearby occupied West Bank, where U.S.-backed Palestinian President Mahmoud Abbas governs in uneasy coordination with Israel.

Medics said five Palestinians were killed in separate incidents near the cities of Nablus and Hebron, including one shooting that witnesses blamed on an apparent Jewish settler.

On Thursday night, 10,000 demonstrators marched in solidarity with Gaza near the Palestinian administrative capital Ramallah - a scale recalling mass revolts of the past. Protesters surged against an Israeli army checkpoint, throwing rocks and Molotov cocktails, and Palestinian medics said one was shot dead and 200 wounded when troops opened fire.

Israel said an army reservist was killed in Gaza on Friday, bringing to 34 the number of soldiers lost in a ground advance it says aims to destroy dozens of cross-border tunnels used by Hamas to threaten its southern farming villages and army bases.

It also announced that a soldier unaccounted for after an ambush in Gaza six days ago was definitely dead, although his body had not been recovered. Hamas said on Sunday it had captured the man, but did not release a photograph of him.

Israeli fire on Gaza continues to cause destructio …Play Video

Three civilians have also been killed in Israel by rockets from Gaza - the kind of attack that surged last month amid Hamas anger at a crackdown on its activists in the West Bank, prompting the July 8 launch of the Israeli offensive.

NEGOTIATIONS

Israeli Prime Minister Benjamin Netanyahu convened his security cabinet on Friday to discuss a limited humanitarian truce under which Palestinian movement would be freed up to allow in aid and for the dead and wounded to be recovered.

A Palestinian official close to the negotiations said Turkey and Qatar had proposed a 7-day halt to the fighting, which had been relayed to Israel by Kerry while Hamas considered it.

An Israeli official acknowledged that the proposal had been received, but said any decision by the Netanyahu government would likely come after Hamas had delivered its own response.

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Chief of the Islamist Hamas movement Khaled Meshaal holds a press conference in the Qatari capital D …

Israel insists that, even if such a ceasefire is agreed, its army will continue digging up tunnels along Gaza's eastern frontier, a mission that could take between one and two weeks.

Netanyahu has said a truce should also lead to the eventual stripping of Gaza's rocket arsenals - something Hamas rules out.

"We must stop the rocket launches. How this is done - whether through occupying (Gaza), or broadening (the operation), or (international) guarantees, or anything else, I have to see it with my own eyes," said police minister Yitzhak Aharonovitch.

The rockets have sent Israelis regularly rushing to shelters and dented the economy despite Iron Dome's high rate of success.

A Hamas rocket intercepted near Ben Gurion Airport on Tuesday prompted the U.S. Federal Aviation Administration (FAA) to halt American commercial flights to Israel's main international gateway. Some European carriers followed suit.

Sixteen Killed in U.N. School Shelling in GazaPlay Video

Jolted by the blow at the height of an already stagnant summer tourism season, Israel persuaded U.S. authorities to lift the flight ban on Thursday, after which the European aviation regulator removed its own advisory against flying to Ben Gurion.

In the second such salvo in as many days, Hamas said it fired three rockets at the airport on Friday, an apparent bid to cripple operations there again. There was no word of impacts at Ben Gurion, whose passenger hall emptied at the sound of sirens.

HAMAS WANTS GAZA OPENED UP

Hamas leader Khaled Meshaal had on Wednesday voiced support for a humanitarian truce, but only if Israel eased restrictions on Gaza's 1.8 million people. Hamas wants Egypt to open up its border with Gaza, too, and demands that Israel release hundreds of prisoners rounded up in the West Bank last month following the kidnap and killing of three Jewish seminary students.

Such concessions appear unlikely, however, as both Israel and Egypt consider Hamas a security threat.

One Cairo official said next week's Eid al-Fitr festival, which concludes Ramadan, was a possible date for a truce. But U.S. officials were circumspect on progress made by Kerry, whose mediation has involved Egypt, Turkey, Qatar and Abbas, as Washington, like Israel and the European Union, won't deal directly with Hamas, which it considers a terrorist group.

"Secretary Kerry has been on the phone all morning, and he will remain in close touch with leaders in the region over the course of the morning as he continues work on achieving a ceasefire,” said a senior U.S. State Department official in Cairo, which has been Kerry’s base over the last four days as he has tried to bring about a temporary end to the conflict.

On Thursday, a U.S. official said Kerry was seeking a way of bridging gaps between Israel and Hamas but that the diplomat would not stay in the region "for an indefinite amount of time".

More than 140,000 Palestinians have been displaced in Gaza by the fighting, many of them seeking shelter in buildings run by the United Nations Relief and Works Agency (UNRWA).

An UNRWA spokesman said the agency had tried in vain to arrange with Israel to evacuate civilians from the school in northern Beit Hanoun before it was shelled on Thursday.

Scores of crying families who had been living in the school ran with their children to a hospital a few hundred meters away where the victims were being treated. Laila Al-Shinbari, who was at the school when it was hit, told Reuters that families had gathered in the courtyard expecting to be evacuated shortly in a Red Cross convoy.

"All of us sat in one place when suddenly four shells landed on our heads ... Bodies were on the ground, (there was) blood and screams. My son is dead, and all my relatives are wounded, including my other kids," she said, weeping.

(Additional reporting by Ori Lewis in Jerusalem, Noah Browning in Gaza, Arshad Mohammed, Yasmine Saleh and Shadia Nasralla in Cairo; Writing by Dan Williams and Crispian Balmer; Editing by Will Waterman and Giles Elgood)

Secretary of State John Kerry presses for a humanitarian cease-fire after another bloody day of fighting.
Shells hit U.N. school

PARIS (AP) — French soldiers recovered a black box from the Air Algerie wreckage site in a desolate region of restive northern Mali on Friday, officials said. Terrorism hasn't been ruled out as a cause, although officials say the most likely reason for the catastrophe that killed all 118 people onboard is bad weather.

More than 200 troops are guarding the site before French accident and criminal investigators arrive Saturday, French Foreign Minister Laurent Fabius said.

The debris field is in a concentrated area in the Gossi region of the northwestern African country near the border with Burkina Faso "in a zone of savannah and sand with very difficult access, especially in this rainy season," Fabius said at a news conference in Paris with the defense and transport ministers.

French government officials, including President Francois Hollande and Fabius, revised the death toll to 118, without explaining the reason for the change. They also raised the number of French killed to 54 from 51. Air Algerie and private Spanish airline Swiftair, which was operating Flight 5017, said Thursday there were 116 people onboard.

"We think the plane went down due to weather conditions, but no hypothesis can be excluded as long as we don't have the results of an investigation," Interior Minister Bernard Cazeneuve told RTL radio hours before the news conference with three other government ministers.

The pilots of the MD-83, which was traveling from Burkina Faso to Algeria, had sent a final message to ask Niger air control to change its route because of heavy rain, Burkina Faso Transport Minister Jean Bertin Ouedraogo said Thursday.

One of two black boxes has been found and was sent to Gao, a troubled city in northern Mali where remains will be sent for identification before being repatriated, Fabius said at Friday's news conference. The Gossi region where the accident occurred, near the Burkina Faso border, is 160 kilometers (100 miles) south of Gao.

A French contingent of troops is based in Gao, a government-controlled town. The vast deserts and mountains of northern Mali fell under control of ethnic Tuareg separatists and then al-Qaida-linked Islamic extremists after a military coup in 2012.

French forces intervened in January 2013 to rout Islamist extremists controlling the region. A French soldier was killed earlier this month near the town of Gao, where French troops remain.

The intervention scattered the extremists, but the Tuaregs have pushed back against the authority of the Bamako-based government. Meanwhile, the threat from Islamic militants hasn't disappeared, and France is giving its troops a new and larger anti-terrorist mission across the region.

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Map shows path of Flight 5017, Algeria and Burkina Faso.

French television showed images of the wreckage site taken by a soldier from Burkina Faso. The brief footage showed a desolate area with scattered debris that was unrecognizable. There were bits of twisted metal but no identifiable parts such as the fuselage or tail, or victims' bodies. Scrubby vegetation could be seen scattered in the background.

A French Reaper drone based in Niger spotted the wreckage after getting alerts from Burkina Faso and Malian soldiers, Defense Minister Jean-Yves Le Drian told reporters.

Burkina Faso soldiers were reportedly the first to reach the site. The country's prime minister, Luc Adolphe Tiao, reviewed videos of the wreckage site and said identifying the victims will be challenging.

"It will be difficult to reconstitute the bodies of the victims," Tiao said at a news conference. "The human remains are so scattered."

Nearly half of the victims were from France and the disaster has hit the country hard.

"I share the pain of families living through this terrible ordeal," Hollande said.

Many of the passengers were scheduled to head on to Europe after the plane was due to arrive in the Algerian capital from Burkina Faso's capital, Ouagadougou.

Hollande has said that France will spare no efforts to uncover why the plane went down — the third major plane disaster around the world within a week. A Malaysia Airlines flight was shot down last week over war-torn eastern Ukraine. The U.S. has blamed it on separatists firing a surface-to-air missile. On Wednesday, a Taiwanese plane crashed during a storm, killing 48 people.

"There are hypotheses, notably weather-related, but we don't rule out anything because we want to know what happened," Hollande said. "What we know is that the debris is concentrated in a limited space, but it is too soon to draw conclusions."

Cazeneuve also said on RTL radio: "Terrorist groups are in the zone. ... We know these groups are hostile to Western interests."

The plane, owned by Swiftair and leased by Algeria's flagship carrier, disappeared from radar screens less than an hour after it took off early Thursday from Ouagadougou for Algiers.

The MD-83 had passed its annual air navigation certificate renewal inspection in January without any problems, Spanish Deputy Prime Minister Soraya Saenz de Santamaria said Friday. The European Aviation Safety Agency also carried out a "ramp inspection" — or unannounced spot check — of the plane in June without incident.

Santamaria also said a ramp inspection was done on the plane in Marseille, France, on July 22 — two days before the plane went down.

Ramp inspections "are limited to on-the-spot assessments and cannot substitute for proper regulatory oversight," the EASA website says. "Ramp inspections serve as pointers, but they cannot guarantee the airworthiness of a particular aircraft."

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AP journalists Ciaran Giles in Madrid, Spain, and Brahima Ouedraogo in Ouagadougou, Burkina Faso, contributed to this report.

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Islamic State destroys the Tomb of Jonah

The new jihadist rulers of Iraq's northern city of Mosul on Thursday completely levelled one its most well-known shrines, an official and witnesses told AFP.

The Nabi Yunus shrine was built on the reputed burial site of a prophet known in the Koran as Yunus and in the Bible as Jonah.

"Islamic State completely destroyed the shrine of Nabi Yunus after telling local families to stay away and closing the roads to a distance of 500 metres from the shrine," said the official at the Sunni endowment, which manages Sunni religious affairs in Iraq.

The endowment official, who spoke on condition of anonymity, and Mosul residents told AFP it took the Sunni extremists an hour to rig the shrine with explosives.

"They first stopped people from praying in it, they fixed explosive charges around and inside it and then blew it up in front of a large gathering of people," said a witness who did not wish to give his name.

The endowment official said the Islamic State jihadist group that overran large swathes of northern and western Iraq last month have now destroyed or damaged 30 shrines, as well as 15 husseiniyas and mosques in and around Mosul.

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This undated file image posted on a militant website on Tuesday, Jan. 14, 2014, which has been verif …

Husseiniyas are Shiite places of worship that are also used as community centres.

The official listed the most notable losses to Muslim heritage as being the shrines of Imam Yahya Ibn al-Qassem, Aoun al-Din and Nabi Danial.

"But the worst destruction was of Nabi Yunus, which has been turned to dust," he said.

The Islamic State late last month proclaimed a "caliphate" spanning parts of Iraq and Syria.

The group aims to create an approximation of society as it was in the early days of Islam, which was founded in the 7th century, and considers Muslims who do not adhere to its puritanical version of the religion heretics.