Investigation are under way into the incident that occurred in the town of Alishir, provincial government spokesman Talib Mangal said on January 26.
The motive behind the attack is not yet known, Mangal added.
There was no immediate responsibility for the attack, which happened late on January 25.
Elsewhere in Afghanistan, a bystander was killed and four other civilians were wounded when a police vehicle hit an improvised explosive device in the capital, Kabul, police said on January 26.
The vehicle was destroyed in the blast, which occurred on the evening of January 25, Interior Ministry spokesman Nusrat Rahimi said.
No group claimed responsibility for the attack, but the Taliban often targets Afghan security forces.