Two US soldiers and an Afghan soldier were killed Saturday as an individual wearing Afghan uniform opened fire on them with a machine gun in eastern Afghanistan, the US military and two senior Afghan officials confirmed on Sunday.
The shootout also wounded six US service members and three Afghan soldiers.
The firefight broke out after a joint US-Afghan force finished a “key-leader engagement” at the administrative headquarters of Nangarhar province’s Shirzad district, a spokesman for US forces in Afghanistan said.
About 14,000 American troops are stationed in Afghanistan as part of the US-led NATO mission to train, assist and advise Afghan forces and to carry out counter-terrorism operations.
“Current reports indicate an individual in an Afghan uniform opened fire on the combined US and Afghan force with a machine gun,” Colonel Sonny Leggett said in a statement, Reuters reported.
“We are still collecting information and the cause or motive behind the attack is unknown at this time,” he added.
The Taliban has not claimed responsibility for the attack and senior officials were investigating whether it was an insider attack - often known as “green-on-blue” attacks that have been a regular feature of the conflict in Afghanistan.
Sohrab Qaderi, a provincial council member in Nangarhar, said the attacker was killed in the clash.
He said the militant had infiltrated the Afghan security forces involved in the joint operation, but did not say which group he belonged to.
According to Reuters, there have been fewer insider attacks in recent years as the US have taken more of a supporting role, with Afghan forces leading the fight.