The US military said three US soldiers and two Iraqi security officials were killed today by a bomb attack on their patrol about 30 kilometres north of Baghdad.
Lieutenant Colonel William Macdonald of the 4th Infantry division said a Bradley armoured vehicle was hit by a roadside bomb near the town of Taji.
Five people, including three US soldiers and two Iraqi civil defence officials, were killed and two soldiers were wounded, he said.
He said three Iraqi men travelling in a truck in the area were arrested after troops found bomb-making material in their vehicle.
The Bradley, with its caterpillar tracks and swivelling gun barrel, resembles a small tank, suggesting the bomb was very powerful. Previous attacks on US convoys have tended to cause casualties aboard lighter vehicles like trucks and Humvee four-seater cars.
The deaths within the "Sunni triangle" north and west of Baghdad, where resistance to US forces has been fiercest, take the number of US soldiers killed in Iraq since the war began to 499, including 153 killed in accidents.