The incident has taken place at Chawk-e-Pista area of Qala-e-Naw at around 12:40 pm on Saturday
Nastrat Rahimi, a spokesman for Interior Ministry said that the clashes broke out after three “suicide bombers” entered the building.
He said that two of the assailants have been killed as fighting continues between security forces and militants in the building.
At least four people including a police commander were killed and nine others including two women and two children were wounded in the incident, head of the provincial public health Abdul Latif Rustai said.
Meanwhile, the Taliban militant group in a statement claimed responsibility for the attack.