KABUL — Five NATO service members were killed in an apparent friendly fire incident in southern Afghanistan, the international coalition said on Tuesday. A statement from the coalition said all five soldiers died on Monday but did not give further details on the attack or the nationality of the soldiers. Coalition policy is for home countries to identify their military dead. Most of the forces operating in the area are from the United States.“The casualties occurred during a security operation when their unit came into contact with enemy forces. Tragically, there is the possibility that fratricide may have been involved. “The incident is under investigation. Our thoughts are with the families of those killed during this difficult time,” the coalition said in an announcement. If confirmed, it would be one of the most serious cases involving coalition on coalition friendly fire during the nearly 14 year Afghan war. One of the worst came in April 2002 when four Canadian soldiers were killed when an American F-16 dropped a bomb on them near a night firing exercise in the southern Kandahar. A senior police official in southern Zabul province said the coalition soldiers may have been killed when they called in for close air support. — AP