Two US soldiers were killed and three wounded when their convoy was targeted in a roadside bomb blast on Sunday near the Iraqi town of Samarra, the US military said.
"Two 1st Infantry Division soldiers assigned to Task Force Danger were killed and three other soldiers were wounded in an improvised explosive device attack on their convoy near Samarra at about 16:29 (12:29 GMT)," it said.
In earlier violence, three people were killed, including a soldier from the US-led forces, when a military convoy was hit by a roadside bomb south of Iraq's main northern city of Mosul on Sunday, the US military said.
Another soldier was also wounded in the blast.
While the injured soldier was being treated following the explosion, a vehicle approached at high speed and fired on the convoy.
The soldiers returned fire killing the driver, the military's statement said.
The roadside bomb explosion also killed an Iraqi citizen that was driving behind the convoy, the statement said.
The statement did not specify the soldiers' nationalities, but the force has small numbers of Albanian and Australian troops alongside the main US force.
Four US marines were killed in a vehicle accident while conducting operations in an area of western Iraq that has strongly resisted US presence in the country.
Several US marines have been
killed in Anbar province
US officials said on Sunday that the four died in Anbar province, an area west of Baghdad that includes Ramadi, Falluja and Qaim on the Syrian border.
"The deaths were as a result of a vehicle accident in the Camp Falluja area and are considered non-hostile," said a military spokesman.
Earlier, the US military had said the four marines died on Saturday "while conducting security and stability operations" without elaborating on the precise cause of death.
The marines said on Saturday they had fought a gun battle with at least seven black-clad fighters in Ramadi.
Witnesses accused the marines of firing for no reason. Military officials said the marines were returning fire.
They said they had killed two of the fighters and suffered no fatalities of their own.
Two Iraqis were killed and six wounded, including two children, hospital staff said.