Iranian President Mahmoud Ahmadinejad said on Saturday the September 11, 2001 attacks were exaggerated in a fresh broadside at the United States just days after President Barack Obama voiced willingness to talk to Iran.

Well-known for his anti-American and anti-Israeli rhetoric, the hardline populist Ahmadinejad also repeated his denial of the Holocaust, on which the consensus of historians is that six million Jews were exterminated by Nazi Germany.

Ahmadinejad said the Sept. 11 attacks with hijacked airliners on New York and Washington D.C. had been trumped up as an excuse for the United States to invade Afghanistan and Iraq.

Speaking at a Tehran conference, Ahmadinejad said there was no evidence that the death toll at New York's World Trade Center, destroyed in the attacks, was as high as reported and said 'Zionists' had been tipped off in advance.

'What was the story of Sept. 11? During five to six days, and with the aid of the media, they created and prepared public opinion so that everyone considered an attack on Afghanistan and Iraq as (their) right,' he said in a televised speech.

No 'Zionists' were killed in the World Trade Center, according to Ahmadinejad, because 'one day earlier they were told not go to their workplace'.

'They announced that 3,000 people were killed in this incident, but there were no reports that reveal their names. Maybe you saw that, but I did not,' he told a gathering of the Iranian news media.

There is a published list of Sept. 11 dead from more than 90 countries available online. A total of 2,995 people were killed in the attacks, including 19 hijackers and all passengers and crew aboard four commandeered airliners, according to official US figures.

The United States blamed the assaults on al Qaeda, led by Saudi-born Osama Bin Laden. Ahmadinejad accused the US government of exercising more media censorship than anywhere in the world.

He had previously said the '9-11' attacks were a 'big fabrication' and has rejected the historical record of the Holocaust. On Saturday, Ahmadinejad repeated his belief that the Holocaust had been invented to justify the creation of Israel.

'They made up an event, the so-called Holocaust which was later laid as the basis for the innocence of a group,' he said.

Ahmadinejad last week challenged Obama to a televised debate on global issues during his trip to the United Nations General Assembly in New York in September.

Two years ago he asked to visit the site of the World Trade Center 'to pay his respects' but New York police refused.

Washington succeeded in June in getting a fourth round of UN Security Council sanctions imposed on Iran to pressure it to suspend its disputed nuclear programme.

Tougher US and European measures have further tightened restrictions on doing business with the major Opec country.

Obama signalled on Thursday he was open to talks with the Islamic Republic and was seeking 'a clear set of steps that we would consider sufficient to show that they are not pursuing nuclear weapons'.

Ahmadinejad has said he is prepared to return to international talks, which were last held in October, but insists that Iran has the sovereign right to enrich uranium.

Western powers fear the Islamic Republic aims to stockpile the material for possible use, when more highly enriched, in nuclear weapons, and UN nuclear inspectors cite indications that Iran is researching how to build a nuclear-tipped missile.

Tehran says it is refining uranium only for electricity and medical treatments. Israel considers the combination of Ahmadinejad's Holocaust denial and his pursuit of nuclear technology a potential threat to its existence and has said it does not rule out military action to prevent Iran developing atomic bombs.

A Washington-based think-tank with access to intelligence said on Friday Iran had begun using recently installed equipment to enrich uranium more efficiently, a step it said could be justified nominally on civilian grounds but in fact made more sense in the context of learning how to make bomb-grade uranium.-Reuters