Two Americans were killed in a shooting by Afghan security forces on Saturday, the latest in a string of ‘insider’ or ‘blue-on-green’ killings of NATO troops, the Financial Times reports.

Nato forces announced Sunday morning that an American soldier – the 2,000th US troop fatality in the conflict – and a civilian contractor were killed after a “suspected insider attack”. According to reports, the shooting happened at around 5 p.m. at an army checkpoint near a joint US-Afghan base in Wardark province. Two Afghan soldiers have also died, but it was not clear whether the aggressor was one of them, provincial government spokesman Shahidullah Shahid said.

NATO lost over 50 foreign troops to “insider killings” perpetuated by Afghan soldiers and policemen. Several Afghan soldiers were also killed in the same circumstances, underlining the growing mistrust between NATO forces and Afghan partners. NATO commanders retrenched integration with Afghan forces to curb infiltration. Coalition forces are conducting joint operations with local security forces in preparation for handing over national security.