The Iraqi government has criticised the US Senate's approval of a bill requiring US troops to leave Iraq.
US troops are currently being increased in Baghdad
Ali al-Dabbagh, the main government spokesman, said the decision was "negative" and sent the wrong signals to insurgents.
The controversial measure makes $100bn (£50bn) in further funding for the war conditional on a withdrawal timetable.
Meanwhile Democrat candidates for the US presidency urged President George W Bush not to veto the war funds bill.
Mr Bush says he is committed to his "surge" strategy, under which more US troops are being poured into Baghdad.
The White House confirmed he would carry out his threat to veto any version of the funding bill requiring a timetabled withdrawal.
Earlier, the top US general in Iraq, David Petraeus, said reducing forces could lead to increased violence.
The Senate voted 51 to 46 in favour of the bill, which says the pull-out must start by 1 October this year, and sets a target of completion by 31 March 2008.
'Admission of defeat'
Mr al-Dabbagh said the vote sent the wrong signals to groups thinking of alternatives to the political process, meaning insurgents.
"We see it as a loss of four years of sacrifices," he said.
His words echoed those of Iraqi Foreign Minister Hoshyar Zebari, who said earlier in the week that "any premature timetable [for withdrawal] would not be realistic".
"This is part of the politicking, basically, in Washington and this has been damaging in fact to the security, political development, not only in Iraq, but in the entire region," Mr Zebari added.
But an MP from radical Shia cleric Moqtadr Sadr bloc said the vote was an admission of US defeat in Iraq.
A prominent Kurdish MP, Mahmoud Othman, said US politicians were simply preparing the ground for the forthcoming presidential elections, while a Sunni representative said the US vote was not the business of Iraqis.
The BBC's Andrew North in Baghdad says the differences of opinion reflect how Iraq's own government is divided over what to do.
Senate Majority Leader Harry Reid described the vote as "a responsible plan for redeployment, not a precipitous withdrawal".
Republicans dismissed the bill as a futile stunt, since although the Democrats control both houses of Congress, they do not have enough votes to overrule a presidential veto.
It is the first time Democrats have managed to summon the support to send a bill opposing Mr Bush's war directly to the president's desk.
The bill may be presented to him on Tuesday, the fourth anniversary of his speech declaring the battle of Iraq a "victory" in the war on terror.
Mr Bush has described efforts to force a withdrawal as an attempt to "handcuff our generals".
But in the first TV debate of the November 2008 election, all eight Democrat contenders for the presidency attacked Mr Bush's policy.
"If this president does not get us out of Iraq, when I am president, I will," said New York Senator Hillary Clinton.
Another front-runner for the Democratic nomination, Illinois Senator Barack Obama, said: "We are one signature away from ending this war."