U.S. President George W Bush pledged Monday to ensure "an outcome that will merit the sacrifice" of those who have died in Iraq, offering both sympathy and resolve as the U.S. death toll in the five-year war hit 4,000.
The U.S. military death toll in Iraq hit 4,000 after the slaying of four soldiers in Baghdad, prompting Bush to send his "deepest sympathies" to the bereaved families on Monday.
The four were killed when their vehicle was hit by a roadside bomb in south Baghdad late on Sunday, a U.S. military statement said, adding that another soldier was wounded by the blast.
"I offer our deepest sympathies to their families," Bush said, vowing "to make sure that those lives were not lost in vain," on what he called a "day of reflection" honoring the US war dead.
The chaotic conflict, now in its sixth year, has killed 4,000 U.S. soldiers and wounded more than 29,000, according to a tally based on independent website www.icasualties.org.
White House spokeswoman Dana Perino said earlier Bush mourned the loss of every single soldier killed since the conflict started in 2003.
"And he bears the responsibility for the decisions that he made and he also bears the responsibility to continue to focus on succeeding."
Perino said it "may be possible" Bush will decide by Friday on a future drawdown of troops after an ongoing drawdown ends by July.
But the top U.S. commander in Iraq General David Petraeus and Defense Secretary Robert Gates favor a pause before any further withdrawal.
Perino said it was "not unlikely" that Bush would accept a pause after July, saying: "The president thinks that there's some merit in that recommendation."
The icasualties.org website, based only on published reports, shows that around 8,000 members of the Iraqi security forces have also been killed since the March 2003 invasion.
At least 97% of the deaths occurred after Bush announced the end of "major combat" in Iraq on May 1, 2003, as the military became caught between a raging anti-U.S. insurgency and sectarian strife unleashed after Saddam Hussein's Sunni-dominated regime was overthrown.
According to the icasualties.org website, 81.3% of military deaths were in attacks by al-Qaida in Iraq fighters, Sunni insurgent groups loyal to Saddam or radical Shiite militias.
The remainder died in non-combat related incidents. Roadside bombs caused most of the fatalities, with gunfire the second biggest killer.
The U.S. dead include 102 servicewomen.
The military death toll is a key issue for Hillary Clinton and Barack Obama as they battle to be the Democrat candidate in this year's U.S. presidential election. Both want U.S. troops out of Iraq.
"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," Obama said in a statement on Monday.
Clinton also promised to bring the troops home.
"I have looked those men and women in the eye. I have made that promise. And I intend to honour it by bringing a responsible end to this war, and bringing our troops home safely," she said.
The deadliest war for the U.S. military, apart from the two world wars, has been Vietnam, with 58,000 soldiers killed between 1964 and 1973 -- an average of 26 a day. On average just over two U.S. soldiers die in Iraq every day.
The icasualties.org statistics reveal that the deadliest year for the military in Iraq was 2007 when it lost 901 troops after a controversial "surge" which saw an extra 30,000 soldiers deployed in a bid to end the violence that has killed tens of thousands of Iraqis.
That figure compares with 486 deaths in 2003, the first year of the conflict, 849 in 2004, 846 in 2005 and 822 in 2006.
This year 96 soldiers have died.
American commanders in Iraq acknowledge that putting extra troops on the ground has exposed them to more attacks, but they also say it has helped curb violence and that attacks have dropped 60% since last June.
The western Sunni province of Anbar witnessed highest overall U.S. casualties, with 1,282 losses, according to icasualties.org, followed by Baghdad with 1,255, Salaheddin with 376, and Diyala with 238.© Wire reports