Updated

An Afghan official says a member of a state-backed militia has shot and killed five fellow militiamen in the latest insider attack among the country's embattled security forces.

Hayatullah Amiri, a district governor in the northern Kunduz province, says the shooting happened early Friday when the militiaman attacked his colleagues in their sleep at the checkpoint they were guarding. The gunman then made off with weapons and ammunition.

No one immediately claimed the attack, but the Taliban has been behind similar assaults in the past, in which Afghan soldiers or police have attacked each other or U.S. troops fighting alongside them.