BEIRUT (Reuters) - At least 65 people, apparently shot in the head, were found dead with their hands bound in a district of the northern Syrian city of Aleppo on Tuesday, activists said.

The British-based Syrian Observatory for Human Rights, which says it provides objective information about casualties on both sides of Syria's war from a network of monitors, said the death toll could rise as high as 80. It was not clear who had carried out the killings.

Opposition activists posted a video of a man filming at least 51 muddied male bodies alongside what they said was the Queiq River in the rebel-held Bustan al-Qasr neighborhood of Aleppo.

The bodies had gunshot wounds to their heads, and their hands were bound. Blood was seeping from their heads and some of them appeared to be young, possibly teenagers, and dressed in jeans, shirts and sneakers.

The Queiq River rises in Turkey and travels through government-held districts of Aleppo before it reaches Bustan al-Qasr.

"They were killed only because they are Muslims," said a bearded man in another video said to have been filmed in central Bustan al-Qasr after the bodies were removed from the river. A pickup truck with a pile of corpses was parked behind him.

It is hard for Reuters to verify such reports from inside Syria because of restrictions on independent media.

Government forces and rebels in Syria have both been accused by human rights groups of carrying out summary executions in the 22-month-old conflict, which has claimed more than 60,000 lives.

Rebels pushed into Aleppo, Syria's most populous city, over the summer, but are stuck in a stalemate with government forces. The city is divided roughly in half between the two sides.

The revolt started as a peaceful protest movement against more than four decades of rule by President Bashar al-Assad and his family, but turned into an armed rebellion after a government crackdown.

More than 700,000 people have fled, the United Nations says.

REBELS FIGHT KURDS

In the eastern city of Deir al-Zor, insurgents including al Qaeda-linked Islamist fighters captured a security agency after days of heavy fighting, according to an activist video issued on Tuesday.

The fighters freed prisoners from the building, it added.

The video, posted online, showed men armed with assault rifles cheering as they stood outside a building that they said was a local branch of Syria's intelligence agency.

Some of the fighters carried a black flag with the Islamic declaration of faith and the name of the al-Nusra Front, which has ties to al Qaeda in neighboring Iraq. The video also showed tanks, which appeared to be damaged, and a room containing weapons.

The war has become heavily sectarian, with rebels who mostly come from the Sunni Muslim majority fighting an army whose top generals are mostly from Assad's Alawite sect, an offshoot of Shi'ite Islam. Assad has framed the revolt as a foreign-backed conspiracy and blames the West and Sunni Gulf states.

Fighting also took place in the northern town of Ras al-Ain, on the border with Turkey, between rebels and Kurdish militants, the Observatory said.

The insurgents have been battling fighters of the Kurdish People's Defence Units for about two weeks in the area, and scores of people have died in the violence.

(Reporting by Alexander Dziadosz and Oliver Holmes; Editing by Kevin Liffey)

Article: Second set of NATO Patriot missiles in Turkey go active

Reuters/Reuters - Residents carry a coffin during the funeral of a victim killed in clashes with security forces in Falluja, 50 km (30 miles) west of Baghdad, in this file photo taken January 26, 2013. REUTERS/Thaier Al-Sudani

RAMADI, Iraq (Reuters) - Across Iraq's western desert, thousands of Sunni Muslims block highways, chant and pray in protests against Shi'ite Prime Minister Nuri al-Maliki that grow more defiant by the day.

Their demands are many, but the old Iraqi flags from Saddam Hussein's era and Sunni tribal colors fluttering among them are a clear message to Maliki: Enough, our time has come again.

In Iraqi cities like Ramadi and Falluja, where tribal ties are strong, many Sunnis have harbored a sense of marginalization ever since Saddam's fall and the Shi'ite majority's empowerment.

But the pent-up Sunni anger that erupted a month ago has many worried that Iraq is heading for an explosion of Shi'ite-on-Sunni violence that will divide it along sectarian faultlines.

Already protests are becoming volatile. Iraqi troops shot five people in clashes in Falluja on Friday, illustrating the room for miscalculation with sectarian hardliners and Islamist insurgents trying to steer unrest into crisis.

Just outside Ramadi, Sunni men sleep in tents and pray along a blockaded highway, wrapping themselves in old three-star Iraqi national flags, chanting slogans and waving migwars, the wooden mace that Iraqis used to fight the British in the 1920s.

Defiant banners hung on tents call out: "No to Maliki's Justice" and "I will not leave until I get dignity".

In fiery speeches from clerics and tribal leaders, talk of reforms mixes with calls to topple the Shi'ite-led government and the more radical demand to split away an autonomous Sunni region in Anbar province along Iraq's western flank.

"This is just the culmination of years of injustice against us," said Munim al-Mindeel, a farmer sitting outside a tent decorated with anti-government banners. "Of course this was bound to happen. All pressure brings explosions in the end."

The turmoil has erupted at a risky time. War in next-door Syria, where mostly Sunni rebels are battling President Bashar al-Assad, is feeding the ambitions of Iraqi Islamists eager to see the rise of a Syrian Sunni regime across Anbar's border.

Anbar, a vast desert heartland of mostly Iraqi Sunnis where al Qaeda once fought American forces, makes up a third of Iraq's territory, and adjoins Syria, Saudi Arabia and Jordan.

A year after the last U.S. troops left, the protests are fast evolving into the most dangerous test yet for Maliki and the OPEC country's precarious post-war settlement sharing power among Shi'ites, Sunni Arabs and ethnic Kurds.

Four suicide bombings in recent weeks delivered a reminder of how al Qaeda and Sunni militants want to inflame tensions. Divisions in Sunni ranks between moderates, Islamists and tribal leaders or sheikhs make ending the crisis even more challenging.

"We are in a state of hyper-volatility, even for Iraqi standards, which invites more chances to miscalculate, overreach, overreact," said Ramzy Mardini at Beirut's Iraq Institute for Strategic Studies.

SUNNI HEARTLAND DEMANDS

After defeating a vote of no confidence last year, Maliki looked to have shored up his position among the complex alliances of Shi'ite parties, Kurdish parties and the Sunni-backed Iraqiya party, which are all split into rival factions.

But the Sunni protests have opened up another front for the Shi'ite leader just as he struggles with a dispute over oil with the autonomous Kurdistan region.

With provincial elections in April seen as a test for the 2014 parliamentary ballot, politicians across the sectarian and ethnic divides all have scope to put pressure on Maliki, lawmakers say.

Maliki has appointed a top Shi'ite to negotiate, and has freed hundreds of Sunni detainees. But his concessions look to have come too late for protesters who are turning against Sunni politicians seen as having been co-opted by the government, lawmakers and sheikhs say.

In Ramadi, the tribal leaders want reform of laws they see as unfairly targeting Sunnis: Iraq's Antiterrorism law and the Justice and Accountability law, which aims to weed out members of Saddam's outlawed Baath party.

The so-called debaathification is sensitive for both sects: Shi'ite leaders want guarantees that senior supporters of Saddam will not return to power, Sunnis say they are being denied benefits and jobs where former Shi'ite Baathists are left alone.

"What did I do to be deprived of a pension?" said one former Baath party member at the Ramadi protest camp. "Why do I have to be deprived of my dignity for one thing I did?"

Those demands are especially sensitive in Falluja and Ramadi, where tribal leaders took up arms against American troops after the invasion. Sickened by al Qaeda's tactics, they later turned against insurgents to join with U.S. forces.

The Sunni protests erupted in December after authorities arrested the bodyguards of Sunni finance minister Rafaie al-Esawi, a Falluja native, on terrorism charges. It was a move Sunni leaders believe was part of a campaign against their sect.

"We'll have no choice but to ask for a new government if they keep on ignoring us," Sheikh Hameed al-Shook, an Anbar tribal leader, said in his Ramadi compound, fringed by date palms. "Everything indicates the government wants to cancel out the Sunni identity."

SYRIAN FEARS

Anbar's sheikhs and lawmakers worry that if they are seen to be sidelined, the protests will fall under the control of hardline clerics and Islamists seeking to promote a more radical agenda, including calls for an autonomous Sunni region.

The Iraqi Islamic Party, part of the Muslim Brotherhood, has been a prime mover in a drive to create a Sunni entity along the border with Syria, by force if needed, senior Sunni sources say.

Under the constitution drawn up after the U.S.-led invasion, each province or group of provinces can create a federal region if it wins enough votes in a referendum.

"Radical Islamists want to come to Baghdad, they want to start from scratch, to go back to before 2003," said one Sunni Iraqiya lawmaker.

Al Qaeda's local wing, Islamic State of Iraq, is also regrouping in the deserts of Anbar, and sending some fighters to join Syria's rebels, Iraqi security officials acknowledge.

While moderates called for calm after Friday's deadly clashes, in Falluja, small groups of protesters waved the black jihadist banner of al Qaeda. The group had claimed a suicide bombing that killed a top Falluja lawmaker days earlier.

Maliki, sensitive to Shi'ite worries about former Baathists and Sunni Islamists, warned about protests being hijacked by "remnants of the former regime and al Qaeda and those with a sectarian agenda".

Increasingly, though, for the Shi'ite leadership, Syria's crisis is a key factor in Iraq's own stability.

Should Assad fall it would weaken the sway of Shi'ite Iran, Syria's main regional ally and a key supporter of Shi'ite Islamist parties in Maliki's coalition. Sunni states such as Saudi Arabia, Qatar and Turkey have backed Assad's foes.

After any Syrian collapse, Iraqi Shi'ite officials see Islamist fighters turning their weapons back on Baghdad. Their worst case scenario is a Sunni population in revolt against Baghdad and becoming a magnet for jihadists.

"Everyone is asking where are we heading, no one knows," said one influential Shi'ite leader. "Our biggest fear is that the regime in Syria collapses, then an Iraqi Sunni region will be announced next day, and fighting will erupt."

(Additional reporting by Ahmed Rasheed and Suadad al-Salhy; Editing by Kevin Liffey)