The Twin Towers collapsed after being hit by hijacked airliners
Iranian President Mahmoud Ahmadinejad has described the 9/11 attacks on the Twin Towers in New York as a "suspect event" and queried the death toll.
"A building collapsed and they said 3,000 people had been killed but never published their names," he said in a speech in the holy city of Qom.
He did not mention the planes hijackers flew into the twin skyscrapers.
On the fifth anniversary, the names of 2,749 people killed in New York were read out at a ceremony.
"Four or five years ago a suspect event took place in New York," President Ahmadinejad said.
"Under this pretext they [the United States] attacked Afghanistan and Iraq and since then a million people have been killed only in Iraq," he said in the speech broadcast on state-run television.
Estimates of the number of lives lost in Iraq vary.
A World Health Organization survey in January this year suggested that 151,000 civilians had died between March 2003 and June 2006.
This was roughly in line with Iraqi government estimates, although one study in the Lancet medical journal put the toll at 655,000, while a UK-based polling agency suggested in September 2007 that up to 1.2m people may have died because of the conflict.
The Iranian president made similar remarks about 9/11 last week, on the country's national nuclear day.
"How is it possible that with the best radar systems and intelligence networks, the planes could crash undetected into the towers?" he asked.
Mr Ahmadinejad did not say on Wednesday who he believed had been behind the attacks.
In November 2001, his predecessor as Iranian president, Mohammad Khatami, condemned "the horrific terrorist attacks" of 9/11 in a speech to the UN General Assembly in New York.
They had, he said, been carried out by "a cult of fanatics who had self-mutilated their ears and tongues".