NATO says a combined Afghan and coalition security force has killed two Afghan police officers and wounded three other people during a gunfight in eastern Ghazni district.

The coalition says “individuals” at an Afghan National Security Force checkpoint fired rocket-propelled grenades, mortar, and small arms at the combined security force late Friday.

NATO says the security force “engaged the checkpoint in self-defense” after its members made “multiple attempts” to identify themselves as friendly forces.

Afghan officials were quoted as saying the shooting incident was the result of a “misunderstanding” between international troops and Afghan forces.

There are more than 130,000 foreign troops in Afghanistan as part of a NATO-led coalition, mostly from the United States. All international combat troops are due to leave the country by the end of 2014, but some U.S. troops are expected to remain in an advisory capacity.