An Afghan official says gunmen stormed a checkpoint in Kabul, killing at least three police officers.

Kabul police spokesman Basir Mujahid says three other policemen were wounded in Sunday night's attack on the outskirt of the city. He added that the attackers first threw hand grenades then opened fire on the police in the city's Doghabad area.

Separately, a provincial official in southern Helmand province says at least seven civilians were killed in an airstrike as Afghan forces battled the Taliban late Sunday.

Provincial council chief Attahullah Afghan says three civilians were also wounded in the attack in Greshk district.

Afghan says a gunbattle was underway with the Taliban at that time and that the incident is under investigation.

It's unclear who carried out the strike, U.S. or Afghan forces.