Iranian President Mahmoud Ahmadinejad has used an address to the UN General Assembly to criticise the US killing of Osama Bin Laden as a 9/11 cover-up. His remarks prompted a walkout by diplomats from more than 30 countries, including the US and EU nations.

Mr Ahmadinejad was widely condemned after his speech, during which he also attacked the West, denounced Israel and questioned the Holocaust.

The address came a day ahead of a Palestinian bid for UN membership.

Mr Ahmadinejad`s controversial rhetoric - and the resulting mass walkout - has become almost a staple of the General Assembly`s meetings.

`Message of hostility`

During Thursday`s address he accused Western nations of weakening countries through military intervention and destroying their infrastructures, in order to plunder their resources by making them all the more dependent .

The Iranian leader also railed against Bin Laden`s death, saying the US had killed the main perpetrator [of 9/11] and threw his body into the sea .

He added: Would it not have been reasonable to bring to justice and openly bring to trial the main perpetrator of the incident in order to identify the elements behind the safe space provided for the invading aircraft to attack the twin World Trade Center towers .

White House press secretary Jay Carney told reporters aboard Air Force One that he found it rich that Mr Ahmadinejad would criticise US policy, and accused Tehran of vile mistreatment of its own citizens.

UK Prime Minister David Cameron used his speech to the UN to hit back at Iran.

They do everything they can to avoid the accountability of a free media, he said. They violently prevent demonstrations and, yes, they detain and torture those who argue for a better future.

Hundreds of people protested against the Iranian leader`s appearance at the UN meeting in New York.

Across from the UN headquarters, there were huge banners, one of which read, Down With the Islamic Republic of Iran , while children stamped on a poster of Mr Ahmadinejad.

The foreign ministry of Israel, which boycotted the speech, said in a statement: Once again the Iranian president delivered a message of hostility to the family of nations, threatening world peace and security.

On Friday the UN Security Council is expected to examine a bid to admit the Palestinians as a partial or full member of the UN.

The US has vowed to veto the request, which is also firmly opposed by Israel.

US President Barack Obama has said there can be no short-cut to a negotiated peace deal in the Middle East, BBC reports.