President Bush could announce the formal US response to Iraq's declaration of its weapons programmes in a few days' time, White House officials have said.

In his first public comments on the issue, US Secretary of State Colin Powell said there were problems with the Iraqi document submitted on 7 December.

"We approached it with scepticism and the information I have received so far is that that scepticism is well-founded," Mr Powell said in Washington on Monday.

If the inspectors go to the right site and to the right building and take this kind of samples, I don't think they [the Iraqis] can hide anything David Donahue IAEA lab chief

The Americans have said they will lead a coalition to disarm Iraq by force if it fails to co-operate fully with UN weapons inspectors, who are operating in the country after a four-year absence.

White House spokesman Ari Fleischer said on Monday that "it was abundantly plain, from the will of the United Nations, that this was Iraq's last chance to inform the world in an accurate, complete and full way what weapons of mass destruction they possessed".

Mr Powell said Washington's official response on the document would be forthcoming towards the end of this week, after the chief UN weapons inspector Hans Blix makes his presentation on the 12,000 page document to the Security Council.

Samples

The BBC's Justin Webb in Washington says nothing has yet been set in stone, but it looks as if President Bush himself will deliver America's unfavourable verdict on the Iraqi document.

Our correspondent says it's understood that one of the problems that America will highlight is Iraq's failure to account for chemical and biological agents the country still possessed when the last inspectors let in 1998.

Meanwhile, the first samples collected by inspectors in Iraq have arrived at a laboratory in Austria run by the UN nuclear agency, where they will be analysed for any traces of a nuclear weapons programme.

An initial analysis of the eight samples will take two to three weeks, a spokesman for the International Atomic Energy Agency (IAEA) told the Associated Press news agency. Another 20 samples are expected by the weekend.

IAEA lab: A tiny trace could have a devastating impact

On a landmark visit to Britain the Syrian President, Bashar al-Assad, said he was optimistic the Iraq crisis could be resolved peacefully.

However, the UK Prime Minister, Tony Blair, said there were clear differences in "views and emphasis" over Iraq between him and Mr Assad.

The UN Security Council resolution paving the way for the return of weapons inspectors to Iraq, adopted in November, warns Baghdad of "serious consequences" if it fails to comply with UN disarmament demands.

New inspections

The IAEA has said it hopes to have screening results from the first samples by the time its director, Mohamed El Baradei, reports to the UN Security Council on 27 January.

US forces are on exercise in Kuwait

UN arms inspectors entered six suspect sites on Monday, including a biomedical institute at Baghdad University - the first visit to an academic facility since inspections resumed three weeks ago.

And for a third day running, Monday saw inspectors visit al-Qa'qaa, a site that was involved in the final design of a nuclear bomb before UN teams dismantled the Iraqi nuclear programme following the 1991 Gulf War.

Extra inspectors have now arrived in Iraq, bringing the total to more than 100.