The US military death toll in Iraq has reached 1,000 since March 2003 when US forces invaded, the Pentagon says.
The US is losing soldiers at an average of 2.25 a day
The stark milestone follows a recent surge in fighting and attacks, with more than a dozen US soldiers killed in the last two days alone.
Correspondents say the casualty figures re-open the debate over President Bush's decision to go to war in Iraq, ahead of the November election.
Meanwhile, violence has continued in Baghdad's Sadr City and Falluja.
US forces resumed air strikes against targets in Falluja on Wednesday, with the fighter planes pounding the industrial zone. Two people are reported killed.
About 100 insurgents were killed in the restive town on Tuesday with US marines saying they used air strikes and artillery fire in response to a bomb attack on Monday that killed seven marines and three Iraqi soldiers.
Also on Tuesday, about 40 Iraqis were killed as US forces fought Shia insurgents in a Baghdad stronghold of rebel cleric Moqtada Sadr, health officials said.
Two Italian aid workers and two Iraqis were also kidnapped from their Baghdad offices in broad daylight.
The Pentagon announced late on Tuesday there had been 1,001 military casualties since US-led forces moved in to Iraq to topple Saddam Hussein 18 months ago.
Another US soldier died overnight, bringing the total number to at least 1,002.
He was killed in an attack on a military convoy north of Baghdad.
Of the total number killed, three were civilian contractors. The number of wounded had reached 7,000.
The landmark of 1,000 dead reignites the Iraq war debate
All but 140 of the deaths have come since 1 May 2003, when US President George W Bush declared an end to major combat operations under a banner reading "Mission Accomplished". About three quarters have been in combat situations.
There are no official figures for the number of Iraqi civilians killed in the same period. A group called the Iraq Body Count (IBC) believes the number exceeds 11,000.
The White House paid tribute to those who had lost their lives.
"We remember, honour and mourn the loss of all those that made the ultimate sacrifice defending freedom," said US presidential spokesman Scott McClellan.
He added that the best way to honour them was to continue waging the war on terror to make "the world a safer
place and make America more secure".
US Democratic presidential candidate John Kerry called it a "tragic milestone" and said Americans would always remember their fallen heroes.
"Their sacrifice will not be in vain. We are committed to making the right decisions in Iraq and the right decisions for them here at home," he said.