President George W Bush says he will not accept "anything less than complete victory" in Iraq.
In a major speech defending his war strategy at the US Naval Academy in Annapolis, Maryland, Mr Bush said that setting an "artificial deadline" to withdraw US troops was "not a plan for victory".
The president's address was accompanied by the release of a 35-page White House document titled "National Strategy for Victory in Iraq."
"Americans should have a clear understanding of this strategy," Mr Bush said.
"No war has ever been won on a timetable - and neither will this one," the National Strategy for Victory in Iraq says.
The White House said yesterday that some US troops could leave next year.
Facing growing domestic pressure about his war strategy, Mr Bush said that Iraqi troops are increasingly taking the lead in battle but that "this will take time and patience."
Mr Bush said that Iraqi forces have not always performed well in combat but have made substantial progress in the past year.
"As the Iraqi forces grow more capable, they are increasingly taking the lead in the fight against the terrorists," the president told a supportive audience at the US Naval Academy.
"Our goal is to train enough Iraqi forces so they can carry the fight against the terrorists."
Mr Bush's speech did not break new ground or present a new strategy. Instead, it was intended to bring together in one place the administration's arguments for the war and its strategy on a military, economic and political track.
He said the document was an unclassified version of the strategy that was being pursued in Iraq.
Mr Bush said that Iraqis are stepping forward to provide security for their embattled country, torn by suicide bombings, kidnappings and other violence. "Iraqi forces have made real progress," the president said.
He said that more than 120 army and police combat battalions are ready to fight on their own, while 80 other Iraqi battalions are fighting side by side with coalition forces.
"They're helping to turn the tide in the struggle in freedom's favour," the president said.
In the latest incident, gunmen opened fire on a minibus north of Baghdad this morning, killing nine people and wounding two. A police official said ten masked gunmen carried out the attack near the town of Baquba, some 65 km (40 miles) from the Iraqi capital.
The White House plans to release a document on the national strategy for victory in Iraq, which officials say will mainly reiterate policies that have already been in place.
White House spokesman Scott McClellan described the document as "an unclassified version of the plan that we have had in place and the plan that we've been pursuing."
The White House is on the offensive against critics who say the United States has become mired in a conflict without a strategy for winning and that it is time to pull troops out.
Democrats say Mr Bush must come out with a specific, concrete exit strategy.
"The American people deserve a clear plan for concluding our military mission. And the Iraqi people need to know without any doubt that we do not intend to stay in that country indefinitely," said Senator Russ Feingold of Wisconsin, a potential 2008 Democratic presidential contender.