Several people were wounded during a clash between Afghan police and NATO-led troops in eastern Nangarhar province on Monday, officials said.

Ahmad Zia Abdulzai, the governor’s spokesman, confirmed the firefight in Achin district to Pajhwok Afghan News. Both sides suffered injuries, he said, without giving further details.

A security official in Achin confided the clash erupted after a policeman, named Sher Ali, fired at International Security Assistance Force (ISAF) troops.

Two US soldiers were wounded, he said, adding an Afghan intelligence operative was killed and a policeman injured in retaliatory fire from US forces. Sher Ali managed to escape.

Meanwhile, ISAF confirmed the shooting by an individual in civilian clothes. A member of the Afghan Uniformed Police, not wearing his uniform, the assailant fired on Afghan and foreign troops.

In response to an email from Pajhwok, the ISAF press office said the attacker fled the scene. “There were no ISAF fatalities. Afghan officials are investigating the incident to determine the facts…”

An Afghan security official with extensive knowledge of southern Afghanistan said the tactic of using assailants embedded in the army or police forces to kill their coalition partners was a particularly worrisome one and had become one of the three main Taliban tactics.