An American marine was killed in Iraq's volatile province of Anbar, the U.S. military said on Tuesday.
The soldier was killed on Monday during combat operations in the southwestern province, the military said in a brief statement.
An earlier military statement said that three more soldiers were killed on Thursday in fighting in the Sunni insurgent stronghold.
The names of the soldiers are being withheld pending notification of next of kin, the statements added.
Anbar province, which stretches from western Baghdad to the Syrian, Jordanian and Saudi borders, has long been the hot bed of insurgency against the American troops since the invasion in 2003.
The latest deaths bring the number of U.S. soldiers have been killed in Iraq to more than 3,650 since the Iraq war broke, according to media count based on Pentagon figures.