Afghanistan, August 17: Two US soldiers have been shot dead by a local policeman in Afghanistan, officials for the international Nato-led force in the country say.

The policeman, reportedly a member of a local defence force being trained by international troops, was also shot and killed, officials said.

The incident happened in the western province of Farah.

It is the latest in a series of so-called “green on blue” attacks by members of the Afghan security forces.

About 130,000 (“blue”) coalition troops are fighting insurgents alongside 350,000 (“green”) Afghans. But there is mounting concern over attacks on Nato troops by their Afghan allies.

Members of the Afghan security forces have killed at least 36 international coalition soldiers this year, in 27 incidents, officials say.