JERUSALEM (Reuters) - Prime Minister Benjamin Netanyahu on Wednesday promised a tough response at the United Nations to the latest verbal attacks on Israeli by Iranian President Mahmoud Ahmadinejad and said he was determined to stop Iran developingnuclear weapons.

Before boarding a flight to New York to address the annual U.N. General Assembly, Netanyahu issued an open letter to Israelis marking the end of Yom Kippur, the Day of Atonement, the most sacred holiday in the Jewish calendar.

"On the question of Iran, we are all united in the goal of preventing Iran from achieving nuclear weaponry. On the day on which we pray to be inscribed in the Book of Life, a stage was given to the tyrannical regime of Iran which seeks at every opportunity to sentence us to death," Netanyahu said.

"On Yom Kippur eve, sacred to the Jewish people, the Iranian tyrant chose to call publicly before all of the world for us to vanish. This is a black day for those who chose to remain in the auditorium and hear these hateful words."

The Israeli leader did not name any U.N. member state in particular. The United States delegation chose not to attend Ahmadinejad's General Assembly speech, while other allies of Israel walked out.

"In statements I will make before representatives of the nations at the U.N. General Assembly, they will hear our response. As prime minister of Israel, the state of the Jewish people, I am working in every way in order that Iran does not have nuclear weaponry," Netanyahu said.

"History proves that those who wanted to wipe us off the map failed in that objective, while the Jewish people overcame all obstacles."

Jews believe that between Rosh Hashana (the Jewish new year) and Yom Kippur, God decides who will be inscribed in the Book of Life, meaning who will not die in the coming year.

Ahmadinejad's speeches in the U.N. forum included a prediction that Israel would be "eliminated".

On Wednesday, with Israelis observing a solemn silence for Yom Kippur, he told the Assembly that Iran was under a "continued threat by the uncivilized Zionists to resort to military action against our great nation".

Iran denies working in secret to develop nuclear weapons, saying that it is building a peaceful atomic power capability. Israel and its main ally the United States have repeatedly said they will not permit Tehran to build the bomb.

Netanyahu's senior advisers privately shrug off Ahmadinejad's incendiary rhetoric, saying he has no policy-making role in Iran's nuclear development program.

On Tuesday, U.S. President Barack Obama told the U.N. Assembly that time was running out to find a diplomatic solution to the Iranian nuclear issue. "The United States will do what we must to prevent Iran from obtaining a nuclear weapon," he said.

That statement went no further than his previously stated position, appearing to ignore calls from Netanyahu urging that Washington must now set clear red lines for Iran, beyond which military action would be taken.

Relations between the men are strained. Netanyahu's office said Obama had declined a request to meet this week, but the two leaders were expected to speak by telephone.

(Reporting by Dan Williams; Writing by Douglas Hamilton; Editing by Kevin Liffey)

Article: Ahmadinejad's aide in prison as Iran president addresses U.N.

5 hrs ago

NEW YORK (Reuters) - Israeli Prime Minister Benjamin Netanyahu will set out, in his speech at theUnited Nations on Thursday, an ultimatum for Iran to halt its disputed nuclear drive or risk coming under military attack, an Israeli official said.

Netanyahu faces the world body after U.S. President Barack Obama disappointed some Israelis, in his own address to the annual assembly, by not calling for a deadline to be imposed on Tehran - though he did say time for diplomacy "is not unlimited".

Israel sees a mortal threat in a nuclear-armed Iran and has long threatened to strike its arch-foe pre-emptively, agitating war-wary world powers as they pursue sanctions and negotiations.

Complicating Netanyahu's strategy have been his testy relations with Obama as a U.S. election looms, and the reluctance of many Israelis to trigger a conflict with Iran, which denies that it is seeking to develop nuclear weapons and has pledged wide-ranging retaliation if attacked.

"The prime minister will set a clear red line in his speech that will not contradict Obama's remarks. Obama said Iran won't have nuclear weapons. The prime minister will clarify the way in which Iran won't have nuclear arms," a senior Israeli official said en route to New York, without elaborating.

Though he has not previously detailed when Israel might be willing to go to war, Netanyahu has said Iran could have enough low-enriched uranium by early 2013 to refine to a high level of fissile purity for a first nuclear device [ID:nL5E8KG2P5].

Israel worries that this final step, if taken, could happen too quickly or quietly to be prevented.

Iran has said it has no plans to enrich uranium beyond the 20 percent purity required to run a reactor producing medical isotopes. That level, however, brings raw uranium exponentially closer to the 90 percent enrichment required for bomb fuel.

Though reputed to have the Middle East's sole nuclear arsenal, Israel would be hard-put to deliver lasting damage to Iran's remote facilities using its conventional forces, or to handle a multi-front war.

WORK TOGETHER

Netanyahu's public calls for a U.S. ultimatum have deepened acrimony with Obama, a Democrat accused by his Republican rivals of being soft on the Jewish state's security. That has stirred American accusations of Israeli meddling in the November presidential elections - something denied by Netanyahu.

"The prime minister will say that Israel and the United States can work together to achieve their common goal," said the Israeli official on condition of anonymity.

Netanyahu, who heads a broad-based, conservative coalition government, departed for New York on Wednesday saying he would take the U.N. podium for an Israel "united in the goal of preventing Iran from achieving nuclear weaponry".

But surveys show that most Israelis - apparently swayed by the open dissent of several senior national-security figures - would oppose launching unilateral strikes on Iran, given the risk of alienating Washington and of provoking clashes with Tehran's Islamist militant allies in Lebanon and Gaza.

A poll published by the liberal Haaretz newspaper on Thursday found that 50 percent of Israelis feared for the survival of their country, should there be a conflict.

Iranian President Mahmoud Ahmadinejad, in his speech to the General Assembly on Wednesday, said Iran was under threat of military action from "uncivilized Zionists," a clear reference to Israel. Earlier this week, Ahmadinejad said that Israel would eventually be "eliminated."

Haaretz also ran excerpts from a leaked Foreign Ministry report that sanctions had caused greater damage to Iran's economy than anticipated by Israel.

The findings, confirmed to Reuters by an Israeli official, could undermine any attempt by Netanyahu to argue that the military alternative must be considered imminently.

Israeli opposition leader Shaul Mofaz criticized Netanyahu for sparring with Obama and voiced confidence in U.S. resolve.

"I am convinced that the United States, the president of the United States, is determined to prevent Iran going nuclear," Mofaz told Israel's Army Radio.

Even within Netanyahu's coalition there have been misgivings about the pitch of disagreement with the United States.

Danny Ayalon, deputy to Foreign Minister Avigdor Lieberman, described Obama's Iran remarks at the United Nations as "important, albeit measured".

Speaking on Israel Radio, Ayalon said the Netanyahu government and Obama administration were in discreet contacts and approaching agreement on setting limits for Iran.

(Writing by Dan Williams; Editing by Angus MacSwan)