The statement gave no details beyond saying the soldiers were assigned to the 2nd Marine Division.
A marine also died in a bomb blast on Saturday in the town of Saqlawiyah, 75km west of Baghdad, the US military added.
The soldiers' deaths came as 10 million Iraqis headed to the polls to vote on a referendum on a draft constitution.
Although there were reports of heavy fighting in Ramadi, the capital, Baghdad, witnessed the lowest level of violence in months.
On Sunday, Ramadi residents reported that heavy fighting continued in the city with US warplanes bombing areas in the east.
Doctor Bassem al-Dulaimi at Ramadi hospital said he had received 25 dead and eight wounded and said relatives had told him the victims had been hit in aerial bombardments.
Residents reported heavy gunfire and clashes in central and eastern parts of the city.
The US military said it had no immediate information on any operations or clashes in the area.
In Falluja, 50km west of Baghdad, two Iraqi soldiers were killed and three wounded when armed men hurled grenades in a market area, police officer Sami Muhammed said on Sunday.
US forces killed 10 fighters in Karabila, 300km west of Baghdad, the US military said on Sunday.