The move comes as the US says it will share intelligence about Iraq with United Nations weapons inspectors following a request from chief inspector Hans Blix.
A BBC correspondent in Washington says the Bush administration now wants the inspectors to have a real opportunity to catch the Iraqis out - and American officials say they are willing to take a chance that revealed intelligence might be leaked to Iraq.
The UN weapons inspectors in Iraq are continuing their investigations as they wait for the Americans to fulfil their pledge to hand over the new intelligence.
Iraqi officials - who deny that they are hiding anything - said the UN team had visited at least five sites in and around Baghdad on what is the 22nd day of inspections.
The US is now preparing for a rapid increase in its military strength in the Middle East, almost doubling the number of troops near Iraq.
In his pre-Christmas radio address on Saturday, Mr Bush asked Americans to remember US troops abroad standing between "Americans and grave danger".
Bush statement
Mr Bush has given the go-ahead for a near-doubling of US forces in the Gulf region.
Defence officials in Washington say the Pentagon plans to move another 50,000 troops next month to join the 60,000 based in the Gulf and Turkey.
UK Prime Minister Tony Blair told the country's armed forces on Friday that they, too, must be ready for a possible confrontation with Iraq.
In his first public response to Iraq's weapons declaration, George W Bush told reporters on Friday that it was "not encouraging".
IRAQI MATERIAL UNACCOUNTED FOR
"We expect Mr Saddam Hussein to disarm," Mr Bush said.
"Yesterday was a disappointing day for those who long for peace," he added.
Baghdad says the initial US response to the declaration was "exaggerated".
"Even before they were able to read and analyse the declaration they said it had many gaps," General Hussam Mohammad Amin, the chief Iraqi officer liaising with the UN weapons inspectors, told the Reuters news agency on Friday.
The United States says that Baghdad was in "material breach" of a critical United Nations resolution - which Washington says gives it the authority to attack Iraq.
Other UN Security Council members, including the UK, Washington's closest ally, have not supported that US interpretation of the resolution.
Pressure
The increase in military pressure on Iraq followed the first report by the UN's chief weapons inspector on Iraq's weapons declaration.
Mr Blix told the Security Council on Tuesday that the document contained little new information.
He said the declaration did not contain the necessary evidence that known weapons of mass destruction had been destroyed.
He will make his report on the weapons document on 27 January.
Baghdad produced its document in accordance with a Security Council resolution passed last month which threatens "serious consequences" if Iraq fails to comply with disarmament demands.
The US says there are a number of steps that must now be taken:
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