Pakistan has condemned the “unprovoked and indiscriminate” firing on civilian population in Chaman by the Afghan border forces, calling on Kabul to take the "strictest possible action".

On Sunday, at least six people were killed and 17 others were injured after heavy weapons including artillery and mortars were used by Afghan forces on the civilians, according to the Inter-Services Public Relations (ISPR).

“Pakistani border troops have given befitting albeit measured response against the uncalled for aggression but avoided targeting innocent civilians in the area,” the ISPR added.

It said Pakistani authorities have approached their counterparts in Kabul to highlight the “severity” of the situation, demanding “strict action to obviate any such recurrence of the incident in future.

Following the shelling, Foreign Office (FO) said that such unfortunate incidents are not in keeping with the brotherly ties between the two countries.

6 civilians killed, 17 hurt by Afghan border forces

"The Afghan authorities have been informed that recurrence of such incidents must be avoided and strictest possible action must be taken against those responsible," it said.

The FO said that it remains the responsibility of both countries to protect civilians along the border.

"The concerned authorities of both countries remain in contact to ensure that there is no further escalation of the situation and recurrence of such incidents is avoided," FO said.

Pakistan's Prime Minister Shehbaz Sharif said the deaths were unfortunate, and "deserve the strongest condemnation."

"The Afghan interim government should ensure that such incidents are not repeated," he said in a statement.

Meanwhile, Reuters reported that Afghan security sources said the clash started after Pakistani forces demanded Afghan forces stop building a new checkpost on their side of the border.

Kandahar police spokesman Hafiz Saber said one Afghan soldier was killed and 10 other people, including three civilians, were injured.

Afghan official Noor Ahmad, in Kandahar, told Reuters the situation had returned to normal after the two sides held a meeting.

The busy Afghan border crossing at Chaman, used for trade and transit, was closed for some hours before reopening, officials on both sides said.

The crossing was closed for several days last month after similar clashes.