Two American soldiers have been shot dead in a gun battle in the Iraqi capital, Baghdad.
US raids have caused bad feeling
The incident, involving the First Armoured Division, took place late on Wednesday evening in the al-Rashid district of the city, according to the US military.
The latest attack brings to 55 the number of US soldiers killed by hostile fire since the war in Iraq was declared largely over on 1 May.
The commander of the US-led forces in Iraq has signalled a change of tactics, because of fears that what he called "iron-fisted" tactics could be provoking acts of revenge.
In the latest attack, about 2300 (1900 GMT) on Wednesday, one soldier died at the scene, and a second died later. A third soldier and an interpreter working with the Americans were wounded.
It is not clear whether any of the attackers were killed or wounded.
In a separate operation overnight, US forces say they have captured a suspected leader of Saddam Hussein militia and two army generals in the former president's home town of Tikrit.
The man is suspected of forming organised cells and paying armed guerrilla fighters to attack coalition forces in the town of Tikrit, according to Lieutenant Colonel Steve Russell.
The US has issued posters, warning children not to carry toy guns
Nearly 400 US troops used Apache attack helicopters, tanks and armoured vehicles to seal off Tikrit, before charging into a local hotel and detaining the men.
Another 40 men - many of whom were labourers - were temporarily held and later released after a stark warning from Colonel Russell.
"If you fight against your government, we will hunt you down and kill you," he told the men through an interpreter, the Associated Press news agency reported.
US forces have been searching for the former Iraqi leader near his ancestral home, and say they are managing to strike a balance between capturing those who are carrying out attacks on their troops and keeping locals on their side.
Change of tack
The commander of the US-led forces in Iraq, General Ricardo Sanchez, has signalled a charge of military strategy in the continuing hunt for supporters of Saddam Hussein.
In an interview in the New York Times, he said that what he called his troops' "iron-fisted" approach was alienating the Iraqi public.
General Sanchez said that the scale of raids in Iraq would now be reduced because they damaged Iraqis' dignity and self-respect and prompted some to acts of revenge.
"When you take a father in front of his family and put a bag over his head and put him on the ground, you have had a significant adverse effect on his dignity and respect in the eyes of his family," he said.
General Sanchez said the new military approach would concentrate more on co-operatin with Iraqi political and religious leaders in an attempt to improve intelligence so that future searches could be more precisely targeted.