Three Nato troops killed by Afghans
Afghan security forces have killed three foreign troops, including two British soldiers, the latest in a growing number of attacks in which Afghan forces have turned their guns on their international partners.
The top commander of US and Nato forces in Afghanistan said such attacks were to be expected when fighting insurgencies.
The two British service members were gunned down by an Afghan soldier in front of the main gate of a joint civilian-military base in southern Afghanistan, according to the US-led coalition.
Another Nato service member, whose nationality was undisclosed, was shot dead at a checkpoint in eastern Afghanistan by a man who was believed to be a member of a village-level fighting force the US is fostering in hopes of countering the Taliban insurgency.
International forces have faced a series of so-called "green on blue" attacks in which Afghan security forces have gunned down their international colleagues or mentors.
Such strikes have become increasingly common over the past year, particularly since the burning of Korans at a US base in February.
Allegations that a US soldier killed 17 Afghan civilians in a shooting spree earlier this month has also stoked sentiment against foreign forces.
US Marine General John Allen told reporters at the Pentagon that these types of attacks are characteristic of any warfare involving insurgents.
"We experienced these in Iraq. We experienced them in Vietnam," he said. "On any occasion where you're dealing with an insurgency and where you're also growing an indigenous force ... the enemy's going to do all that they can to disrupt both the counterinsurgency operations" and the developing nation's security forces.
Sixteen Nato service members, including eight Americans, have been killed by Afghan security officials or militants disguised in their uniforms so far this year. It raises to 80 the estimated number of Nato service members killed by Afghan security forces since 2007.