The province's security chief, Saeed Agha Sagheb, said the attack took place on June 8 in a public market in the Bala Buluk district. A police search for the unknown assailants has so far yielded no results.
In another incident, Afghan officials also say two aid workers were killed in an attack in the northern province of Balkh. One aid worker was injured.
Also on June 8, three Afghan soldiers were killed after their convoy hit a mine or was struck by a roadside bomb in the eastern province of Paktia.