Afghan blast kills four US troops

US troops were on patrol with Afghan forces when attacked

Four US soldiers and nine members of the Afghan security forces have been killed in attacks over the last two days, officials say.

The US troops died in a bomb attack in Oruzgan province, the US military said.

Afghan officials say one Afghan soldier died in Kunar province on Monday, while eight from an Afghan militia unit were killed in Helmand province on Sunday.

More than 130 US soldiers have died in combat in Afghanistan since the US-led invasion toppled the Taleban in 2001.

'Ambush'

A US military statement said the US troops' armoured vehicles struck a bomb while on patrol with Afghan forces, north of Deh Rahwood in Oruzgan province. It said the bomb was thought to have been a homemade explosive device. Air support was called in after ground forces came under fire, it added.

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Afghanistan

In the incident in Kunar province on Monday, a remote-controlled roadside bomb killed one Afghan soldier and injured five others, Shah Mahmoud Saeed, the district governor of Saw, told the BBC.

On Sunday, eight Afghan militia were killed in an ambush in southern Helmand province, by suspected Taleban militants, Afghan officials said.

They said they had found five bodies and were searching for the remaining three. The militia unit had been providing security for American forces.

The US has around 20,000 troops in Afghanistan hunting al-Qaeda and Taleban fighters, mainly in the south and east.