The US and other Western delegations at the 65th UN General Assembly have walked out in protest at the speech of the Iranian president. Mahmoud Ahmadinejad said some saw the 11 September attacks on the US as part of a US conspiracy to protect Israel. Mr Ahmadinejad was speaking on the first day of a week-long UN diplomatic marathon at its New York headquarters. The US denounced his remarks on the 2001 attacks, which killed nearly 3,000 people, as "abhorrent and delusional". The American delegation was joined in its walk-out by representatives from 32 other nations - including all the EU countries, Canada, Australia, New Zealand and Costa Rica. But Mr Ahmadinejad appeared undaunted by the protest, continuing his attack on Zionism and Israel, says BBC diplomatic correspondent Jonathan Marcus. Capitalist 'failures' The Iranian president's speech was part political diatribe, part sermon, adds our correspondent - a wide-ranging presentation of his own particular world view. The Iranian president said he would host a conference on terrorism next year and that 2011 should be the year of nuclear disarmament. Repeating Iran's denial that it was seeking the capacity to build nuclear weapons, Mr Ahmadinejad said some members of the UN Security Council had "equated nuclear energy with nuclear bombs". He also said Tehran would not submit to what he called unnecessary pressure from the the UN nuclear watchdog, the International Atomic Energy Agency. Mr Ahmadinejad had started his speech by outlining what he called the failure of the existing world order and capitalism, saying the world should be run by virtuous people like the Prophets. Although he said that Iran was ready to have a serious discussion with US statesmen, our correspondent says that on the evidence of this speech there would be little for them to talk about. In response to the speech, Mark Kornblau, spokesman for the US mission at the United Nations, told AFP news agency: "Rather than representing the aspirations and goodwill of the Iranian people, Mr Ahmadinejad has yet again chosen to spout vile conspiracy theories and anti-Semitic slurs that are as abhorrent and delusional as they are predictable." At the UN General Assembly, leaders take to the stage to make speeches on a subject of their choice. Iran has already endured four rounds of increasingly punitive economic sanctions over the nuclear dispute. Foreign ministers from countries including the US, UK, China, France, Germany and Russia discussed the issue at a meeting on Wednesday, and it is also likely to be raised on the fringes of the General Assembly. Dozens of fringe meetings take place and correspondents say they constitute the most important business of the event. Peace-keeping in Somalia, the possible break-up of Sudan, the conflict in Yemen, climate change and UN reform are all set to feature in these smaller meetings. 'Hard realities' Speaking shortly after UN Secretary General Ban Ki-moon launched the diplomatic marathon on Thursday, US President Barack Obama urged the audience to support direct Israeli-Palestinian peace negotiations which started on 2 September. He said those longing for an independent Palestine must not try to tear down Israel, and called on Israel to extend a moratorium on building new settlements in the West Bank and East Jerusalem. Mr Obama accepted that many remained pessimistic about the peace process, with cynics saying the two sides were too distrustful of each other, and too divided internally, to forge lasting peace. "Some say that the gaps between the parties are too big; the potential for talks to break down is too great; and that after decades of failure, peace is simply not possible." But the US president called on his fellow leaders to consider the alternative. "If an agreement is not reached, Palestinians will never know the pride and dignity that comes with their own state. Israelis will never know the certainty and security that comes with sovereign and stable neighbours who are committed to co-existence. "The hard realities of demography will take hold. More blood will be shed. This Holy Land will remain a symbol of our differences, instead of our common humanity." In his opening address, Mr Ban urged the nations to stand together in a time of growing challenges and uncertainty. He said the UN provided a moral compass for a world in which social inequalities were growing, with women and children bearing the brunt. He called for a "stronger UN for a better world". Mr Ban said the UN had embraced an ambitious agenda for a more prosperous world free of poverty, and for a greener, safer world free of nuclear weapons. Source: BBC