Islamabad/UNI: Two policemen were killed, and a passerby was injured due to gunfire by unknown gunmen in Pakistan's northwest Swat district on Thursday, police said.

The policemen were deployed at the busy vegetable market in the district as part of the security detail when the militants attacked them in the morning, the Swat police said.

The attackers fled the scene on a motorbike after spraying bullets at the policemen.

Sources from the non-government rescue organization Edhi told Xinhua that the injured person, who is a security guard in a private bank, has been shifted to a hospital, and his condition is critical.

No group has claimed the attack yet.

Police cordoned off the area for investigation, and a search operation is also underway in the surrounding area to find traces of the fleeing assailants.