Three US marines were killed in Iraq's restive Al-Anbar province in clashes with insurgents, the US military reported on Saturday.

The marines, who were assigned to the 1st Brigade, 1st Armored division, died on Thursday in the province, which has long been an insurgent stronghold although it has been spared the brunt of ongoing sectarian fighting.

The latest casualties bring the number of US servicemen killed since the 2003 invasion to 2,571, according to Pentagon figures.