The US House of Representatives has voted in favour of a resolution criticising President George W Bush's decision to send extra troops to Iraq.
Bush's plan to send more troops to Iraq has run into trouble
Seventeen of his Republican Party joined the Democrats in passing the non-binding motion 246 to 182.
The vote follows days of fierce debate, during which the Democrats have made it clear that more decisive steps to limit Mr Bush's war policy could follow.
The Senate is due to vote on Saturday on whether to debate the troop plan.
Previous Senate attempts to debate the anti-troop surge resolution have been met with delaying tactics from Republican members.
If senators do vote to consider the resolution in their unusual Saturday session, Mr Bush faces the possibility that both chambers of Congress will repudiate his Iraq policy within two days, says the BBC's Justin Webb in Washington.
Although both the Congressional resolutions are non-binding, the president needs the legislators to support his $93bn (£48bn) emergency troop funding measure.
"The president believes that the Congress should provide the full funding and flexibility our armed forces need to succeed in their mission to protect our country," the White House said in a statement shortly after the vote.
White House officials said Mr Bush had been too busy to watch the proceedings on television.
The House vote brought to a close the first full debate there since the Democrats took control of Congress in November.
Written by the Democrats, the resolution states that the House "will continue to support and protect" US soldiers in Iraq but that it "disapproves" of the 21,500-strong troop increase.
About 400 of 434 representatives in the House spoke during four days of debate.
Speaking after the vote, House of Representatives Speaker Nancy Pelosi said it would send an unmistakable signal to the White House.
"The president's escalation plan repeats past mistakes. The stakes in Iraq are too high to recycle proposals that have little prospect for success.
"The bipartisan resolution today may be non-binding. But it will send a strong message to the president - we here in Congress are committed to protecting and supporting our troops."
Ms Pelosi had earlier warned there would be "no more blank cheques" for Mr Bush on Iraq.
House Minority Leader John Boehner had urged lawmakers to vote against the motion, saying it was "the first step towards a tragic, unthinkable goal".
"We face a sophisticated, determined enemy who wants to annihilate our way of life," he said.
"We have a duty to stand and fight against those that seek to destroy America and the freedom that defines us."