The crossing at Chaman on the Pakistani side and Spin Boldak in Afghanistan was shut late Thursday after a Pakistani soldier was "abducted" by Afghan troops, Pakistani spokesman Colonel Hassan Jamil told AFP.

The Afghan guards kidnapped the soldier after Pakistani troops refused to allow entry to a group of 12 people who did not have proper travel documents, he said.

"The soldier was however released after some time and the Afghan officials at a meeting later expressed regrets over the incident," he said.

The matter has been resolved but the border remains closed, he said.

The Pakistan side has since told Afghan officials that they would not allow people to cross the border without proper documents, to stop militants or criminals entering the country, he said.

"We hope the border will be reopened on Saturday," Jamil said.

Meanwhile, a remote-controlled bomb and a separate ambush, both claimed by Taliban militants, killed a district chief and three policemen in southern Afghanistan, officials said yesterday.

The bomb was detonated Friday under the vehicle of the head of Shawali Kot district of insurgency-hit southern Kandahar province, deputy head Obaidullah Khan said.