At least three Pakistani civilians were killed and 17 others injured as Afghan border forces opened fire on security personnel guarding a census team in Balochistan on Friday, police said.

The incident took place in Chaman area near the Afghan border, media reported.

The Inter-Services Public Relations (ISPR) issued a statement that said Afghan Border Police opened fire on Frontier Corps (FC) personnel.

Four FC Balochistan men are among those injured.

The ISPR said Friday's firing comes despite the fact that Afghan authorities were informed in advance about the census exercise in the area and coordination was carried out through diplomatic and military channels.

The Chaman border crossing has been sealed as Pakistani and Afghan troops continue to exchange fire, the ISPR press release said.

Pakistan had closed its borders with Afghanistan at Chaman and Torkham on February 18 after a series of terrorist attacks in the country killed over 100 people, media reported.

Militants having sanctuaries in Afghanistan were blamed for the attacks.

After over a month of closure, Prime Minister Nawaz Sharif ordered reopening of the borders as a goodwill gesture.