Two American soldiers have been killed in separate attacks on their convoy in the Iraqi capital Baghdad.
Military officials say the first soldier died in a firefight after two armed assailants opened fire.
The soldiers opened fire, killing one of the attackers and wounding the other. The wounded suspect was taken into custody.
In the second incident, attackers threw a home-made bomb at another US convoy, killing a soldier. The attacks happened on last night and early this morning.
Both those killed were from the Army's Germany-based 1st Armoured Division, which is charged with occupying Baghdad. At least three US troops have been killed in Baghdad in the last 24 hours.
At midday Sunday, an assailant shot dead a US soldier waiting to buy a soft drink at Baghdad University, firing once from close range. The style was coldly similar to the killing of a young British freelance cameraman, who was shot in the head outside a Baghdad museum on Saturday.
The death of the British cameraman Richard Wild, 24, and a grenade attack on a UN compound raised concern that Iraq's worsening uprising - until now targeting only coalition troops and Iraqis accused of US collaboration - would spread to Westerners in general.
US troops on patrol in Baghdad and other areas have been attacked several times a day and Iraqi police and civilians perceived to be working with the occupying forces have also been targeted.
In the most serious attack, a bomb blast in the western town of Ramadi killed seven Iraqi police recruits as they graduated from a US-taught training course on Saturday. Dozens more were injured.
US Army Major William Thurmond said it was too early to tell whether a pattern was emerging that would suggest insurgents are targeting foreign civilians, but he said such a strategy could thwart news gathering and humanitarian relief efforts.