Jason Szenes / EPA
Iranian President Mahmoud Ahmadinejad addresses the 67th session of the United Nations General Assembly at United Nations headquarters in New York Wednesday.
By NBC News staff and wire reports
Iranian President Mahmoud Ahmadinejad complained to the United Nations General Assembly in a speech Wednesday that his country was under the ?continued threat? of military action by ?uncivilized Zionists.?
Ahmadinejad, who is due to leave office next June after serving two four-year terms, was speaking amid growing tensions over claims Iran is secretly trying to develop nuclear weapons, its belligerent language toward Israel and its support for Bashar Assad?s regime in Syria. Iran says its nuclear program is for peaceful purposes only.
Israeli leaders have been openly contemplating military action again Iranian nuclear facilities, dismissing Iran's claims and the idea of a diplomatic solution as a dead end.
Israel and many in the West cite Iran?s failure to cooperate fully with nuclear inspectors as an indication that it is seeking nuclear weapons.
Pugnacious Iranian president rips Israel, US
In his speech, Ahmadinejad complained that the world?s leading powers were forcing others to submit to their wishes.
?Continued threat by the uncivilized Zionists to resort to military action against our great nation is a clear example of this bitter reality,? he said, according to a translator.
President Obama tells the United Nations General Assembly that the US will "do what we must" to stop Iran from getting a nuclear weapon.
Ahmadinejad also asked people to imagine that wars from the Crusades to Iraq and Afghanistan, and other events and practices in history ? such as slavery, colonial oppression, the current global financial crisis and the Sept. 11 attacks on the U.S. -- had not happened.
?Imagine how beautiful and pleasant our lives and how heavenly the history of mankind would have been,? he said.
He put the blame for much of the current problems on the leading countries and called for a new world order. ?The current abysmal situation of the world and the bitter incidents of history are due mainly to the wrong management of the world and the self-proclaimed centers of power,? he said.
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A spokesman for the U.S. mission said the U.S. boycotted Ahmadinejad's speech because of his statements during the last few days -- and because the U.N. scheduled his speech on Yom Kippur.
"Over the past couple of days, we've seen Mr. Ahmadinejad once again use his trip to the U.N. not to address the legitimate aspirations of the Iranian people but to instead spout paranoid theories and repulsive slurs against Israel,? the spokesman said in a statement. ?It's particularly unfortunate that Mr. Ahmadinejad will have the platform of the U.N. General Assembly on Yom Kippur, which is why the United States has decided not to attend.?
Canada's delegation also walked out.
At schools, in shops, and on the streets of big cities and small towns, daily life plays out in Iran.
On Tuesday, President Barack Obama warned the General Assembly that the U.S. would not allow Iran to do develop nuclear weapons.
Obama: US will 'do what we must' to stop Iran getting nuclear weapons
?Make no mistake: A nuclear-armed Iran is not a challenge that can be contained. It would threaten the elimination of Israel, the security of Gulf nations, and the stability of the global economy. It risks triggering a nuclear-arms race in the region, and the unraveling of the non-proliferation treaty,? he said.
?That?s why a coalition of countries is holding the Iranian government accountable. And that?s why the United States will do what we must to prevent Iran from obtaining a nuclear weapon,? he added.
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In an interview with The Associated Press Tuesday, Ahmadinejad said he had no knowledge of the whereabouts of Robert Levinson, a private investigator and former FBI agent who vanished in Iran five years ago.
He said he directed Iranian intelligence services two years ago to work with their counterparts in the U.S. to locate him.
"And if any help there is that I can bring to bear, I would be happy to do so," he said.
He also claimed never to have heard of Amir Hekmati, a former U.S. Marine who is imprisoned on espionage charges in Iran.
Hekmati was arrested while visiting his grandmother in Iran in August 2011, and his family has been using Ahmadinejad's visit to New York to plead for his release.
NBC News' Ian Johnston, The Associated Press and Reuters contributed to this report.
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