US Democratic politicians also condemned the rising death toll in Iraq, with presidential hopeful Barack Obama saying it was "time to end this war".
The White House said earlier on Monday that Bush is likely to adopt an expected recommendation from General David Petraeus, the top US commander in Iraq, that significant troop withdrawals from Iraq are put on hold.
Higher Iraqi toll
The US death toll in Iraq reached 4,000 following the deaths of four soldiers in a roadside bomb attack in the south of the Iraqi capital, Baghdad, on Sunday.
At least 50 Iraqis, most of them civilians, also died on Sunday in violence including bomb blasts and shootings.
More than 29,000 American soldiers have been wounded after years of conflict in Iraq, according to the icasualties.org website, which also carried the 4,000-strong US death toll.
The Iraqi death toll from the US-led invasion is much higher, with estimates ranging from around 90,000 by website Iraq Body Count to upwards of 650,000 in a controversial report by the UK Lancet medical journal released in October 2006.
However Al Jazeera correspondent Rob Reynolds says that although polls show the majority of US citizens have made it clear they think war was a mistake and would like US troops withdrawn, policy makers within the government do not share this view.
Calls to withdraw
Obama said on Monday he reacted "with great sadness" to the news that "we have reached another grim milestone in Iraq, with at least 4,000 of our finest Americans having been killed".
"It is past time to end this war that should never have been waged by bringing our troops home, and finally pushing Iraq's leaders to take responsibility for their future," he said.
Hillary Clinton, Obama's rival for the Democratic nomination, reiterated her belief in a statement that the troops should be withdrawn.
"As president, I intend to honour their extraordinary service and the sacrifice of them and their families by ending this war and bringing them home as quickly and responsibly as possible," she said.