The NATO force confirmed the shooting deaths of two coalition soldiers, saying the attack was carried out by a man believed to be an Afghan soldier and a second Afghan in civilian clothing.

The escalating attacks -- so-called green-on-blue shootings -- have called into question whether an ambitious NATO effort to train Afghan forces to take over responsibility for safeguarding the country can move forward. Handing over security responsibility to the Afghan police and army is central to NATO’s exit strategy.