Insurgents killed seven American servicemen in two separate attacks in Iraq on Thursday, US military officials have said.
Four marines were killed while conducting combat operations in the western province of Anbar. No further details were given.
Three soldiers were killed in the northern province of Nineveh, when their vehicle was caught in a blast.
Eighteen US servicemen have died in operations in Iraq this month.
Levels of violence in the vast, predominantly Sunni province of Anbar had dropped recently. President Bush visited Anbar on Monday and praised the improved security there.
The latest casualties mean more than 3,750 US soldiers have been killed in Iraq since the start of the US-led invasion in 2003.