Iraq's prime minister said the country had won sovereignty and stood as an equal to the United States after the U.S. military formally ended combat operations on Tuesday, despite political deadlock and violence.
U.S. troop numbers were cut to 50,000 in advance of the Aug. 31 milestone as President Barack Obama seeks to fulfil a promise to end the war launched by his predecessor George W. Bush.
The six remaining U.S. military brigades will turn their focus to training and advising Iraqi police and troops as Iraq takes responsibility for its own destiny ahead of a full withdrawal of U.S. forces by the end of next year.
"Iraq today is sovereign and independent," Prime Minister Nouri al-Maliki told Iraqis in a televised address to mark the U.S. forces' shift to assisting rather than leading the fight against a Sunni Islamist insurgency and Shiite militia.
"With the execution of the troop pullout, our relations with the United States have entered a new stage between two equal, sovereign countries."
Obama promised war-weary U.S. voters he would extricate the United States from the war, launched by Bush with the stated aim of destroying Iraqi weapons of mass destruction.
No such weapons were found. Almost a trillion dollars have been spent and more than 4,400 U.S. soldiers and over 100,000 Iraqi civilians killed since the 2003 invasion.
Obama's Democratic party is battling to retain control of Congress in elections in November and his administration faces other challenges — a worsening war in Afghanistan and storm clouds over the economy.
Tuesday's deadline was to some extent a symbolic one. The 50,000 U.S. soldiers staying on in Iraq for another 16 months are a formidable and heavily-armed force.
Iraqi security forces have already been taking the lead since a bilateral security pact came into force in 2009. U.S. soldiers pulled out of Iraqi towns and cities in June last year.
Thanking the soldiersIn Washington, meanwhile, Obama was set to personally thank some of the soldiers who fought there for their service to a mission he forcefully opposed from the start.
Many of those soldiers deployed from Fort Bliss, the sprawling Army base in El Paso, Texas, that Obama will visit Tuesday. After speaking with the troops, Obama will return to Washington to address the nation and formally end a combat mission in Iraq that lasted more than seven years.
Obama was an early critic of the war, speaking out against it during the U.S. invasion and promising during his presidential campaign to bring the conflict to an end.
The White House sees Tuesday's benchmark as a promise kept and has gone to great lengths to promote it as such, dispatching Vice President Joe Biden to Iraq to preside over a formal change-of-command ceremony and raising Tuesday night's remarks to the level of an Oval Office address, something Obama has only done once before.
Among Obama's goals on Tuesday is honoring those who have served in Iraq since the March 2003 invasion, many returning to the battlefield for multiple tours of duty.
White House spokesman Robert Gibbs said Monday that while the Iraq war would have never happened had Obama been commander in chief at the time, the president holds the service and sacrifice of the troops in high regard.
"Whether you are for the invasion or whether you opposed the invasion, you had our men and women in uniform who undertook the commands of their commander in chief, and should be held up and celebrated for what they've done in allowing combat troops now to come home," Gibbs said.
'We'll be fine, they'll be fine' Iraqis are apprehensive as U.S. military might is scaled down, especially amid a political impasse six months after an inconclusive election.
"We'll be just fine, they'll be just fine," Biden said after flying to Baghdad on Monday to mark the end of combat operations and to urge Iraqi leaders to speed up the formation of a new government.
"Notwithstanding what the national press says about increased violence, the truth is things are very much different. Things are much safer," Biden told Maliki on Tuesday before their meeting was closed to the media.
U.S. officials said Washington had a long-term commitment to Iraq, and the military pullback would allow diplomats to take the lead in building economic, cultural and educational ties. For that they need a new Iraqi government to be in place.
Violence in Iraq has declined sharply since the peak in 2006/07 of the sectarian slaughter unleashed by the 2003 U.S.-led invasion, but bombings and killings remain common.
The animosity that led to carnage between majority Shiites and minority Sunnis who had dominated Iraq under dictator Saddam Hussein has not healed, and a potentially explosive conflict between Arabs and Kurds has not been resolved.
More than 1.5 million Iraqis are still displaced after being driven from their homes by violence. Many live in squalor.
Many Iraqis had hoped the March 7 election would chart a path toward stability at a time when deals to develop the country's vast oilfields hold the promise of prosperity.
Instead, the ballot could widen ethnic and sectarian rifts if the actual vote leader, ex-premier Iyad Allawi's Sunni-backed cross-sectarian Iraqiya alliance, is excluded from power by the major Shiite-led political factions.
Suspected Sunni Islamist insurgents linked to al-Qaida have tried to exploit the political vacuum and declining U.S. troop numbers with suicide bombings and assassinations.
The number of civilians killed in July almost doubled from the month before to 396.
The insurgents have targeted domestic security forces in particular, killing 57 at an army recruitment center on Aug. 17 and more than 60 when suicide car bombers attacked police stations around the country on Aug. 25.
Iraqis fear that Shiite Iran, whose influence has already grown apace since Saddam's fall, will seek to fill any vacuum left by the U.S. military, in competition with Sunni-led neighbors such as Turkey and Saudi Arabia.