KABUL: A car bomb attack killed two US soldiers in Afghanistan on Thursday, at the same time that President Hamid Karzai was being sworn in for a second five-year term in the capital, Nato said.

The blast, which an Aghan army soldier called a suicide car bomb, occurred at 0630 GMT, as Karzai's inauguration ceremony got underway.

'Two US service members were killed in an improvised explosive explosion in Zabul province. It was a car bomb,' Lieutenant Nicol Melendez told AFP.

'It was a suicide car bomb,' an Afghan officer told AFP from the scene.

He said the bomber drove his explosives-packed car into the gate of a small US-run military base in the town of Qalat, the capital of Zabul province.

Suicide car bombings have become almost common-place in Afghanistan as a Taliban-led insurgency gathers pace and the death toll of Western troops hits record levels. -AFP