From: hosted.ap.org

KABUL (AP) -- An Afghan policeman opened fire on British soldiers in the volatile southern province of Helmand, killing five before fleeing, British and Afghan authorities said Wednesday, raising concerns about discipline within the Afghan forces and possible infiltration by insurgents.

The attack Tuesday afternoon came a month after an Afghan policeman on patrol with U.S. soldiers fired on the Americans, killing two. Training and operating jointly with Afghan police and soldiers is key to NATO's strategy of dealing with the spreading Taliban-led insurgency and, ultimately, allowing international forces to leave Afghanistan.

Lt. Col. David Wakefield, spokesman for the British forces, told Sky News that the soldiers had been mentoring Afghan national police and had been working and living in the police checkpoint in Helmand's Nad-e-Ali district.

"It is our initial understanding that an individual Afghan policeman possibly acting in conjunction with one other started firing inside the checkpoint before fleeing from the scene," he said.

A Helmand police official said authorities searched through the night and on Wednesday for the attacker. He said the man had been working as a police officer in the area for three years, and had passed through a police academy in Kandahar. The official, who spoke on condition his name not be used because of the sensitivity of the situation, said it was unclear what his motives were.