The first official pictures since his court appearance last July were mute but a tribunal statement said he was being questioned about a 1982 massacre at a Shia village north of Baghdad, one of the cases expected to arise at his trial.

Saddam, 68, wore a dark jacket and open-necked white shirt, a dapper contrast to unofficial images of him in his underpants which were splashed across newspapers last month. It was a subdued appearance compared to the defiance of last July.

In the brief segment he was seated at a desk in a nondescript room, occasionally stroking his beard before answering questions from two magistrates in black robes. Four fellow defendants were also shown.

Saddam's chief lawyer, Khalil al-Duleimi, said he would have to view the video before commenting. The tribunal said Mr Duleimi was present during the filming.

However, a London-based member of the defence team, Giovanni di Stefano, said the former president was without legal assistance during the video and that it would be inadmissible in the trial.

The defence team has accused the tribunal of denying it proper access to the ousted dictator, withholding documents and leaking information to the press.

The video was released as US opinion was hardening against military involvement in the Iraq war, with 59% saying the United States should withdraw some or all of its troops.

As the number of US military casualties topped 1,700, the latest Gallup poll gave the most pessimistic assessment of the war from the American public since it started more than two years ago, with many comparing it to Vietnam.

The number of Americans who thought the US should withdraw some or all of its troops was up 28% on the figure six months after the war began. Meanwhile a majority of those asked said they would be "upset" if President Bush sent more troops, while 36% - a new low - said they wanted troops levels either maintained or increased.

"It appears that Americans are coming to the realisation that the war in Iraq is not being won and may well prove unwinnable," retired Army Colonel Andrew J Bacevich, a professor at Boston University, told the Washington Post. "That conclusion bleeds over into a conviction that it may not have been necessary in the first place."

A Washington Post poll last week revealed that two-thirds of the public believe the US military is bogged down in Iraq while almost three-quarters thought the level of casualties unacceptable. The figures match or exceed the previous high water tide of public disenchantment.

More than half believe the war has not made them safer and 40% believe it has striking similarities to the experience in Vietnam.

Ronald Spector, a military historian at George Washington University told USA Today: "Even some of those who thought it was a great idea to get rid of Saddam are saying: "I want our troops home."

The Iraqi government is impatient for Saddam's trial and recently said it would start within two months but the tribunal, which is independent, said there was no timetable.

The first case is expected to relate to reprisals in Dujail in 1982 after some villagers shot at Saddam's convoy. More serious charges related to the mass slaughter of Kurds and suppression of Shia uprisings will follow.

Detained in a US-run base in Baghdad since his capture in December 2003, Saddam faces the death penalty if convicted of war crimes.