KABUL, Afghanistan -- NATO said Saturday it is investigating whether an Afghan National Army soldier killed two coalition service members in southern Afghanistan, where joint forces are pushing into insurgent strongholds.
NATO said the coalition and the Afghan government were jointly investigating how the two service members died Friday evening in Sangin, a dangerous district of Helmand province.
An insurgent attack killed another NATO service member Saturday in the south, NATO said, without giving details or providing a nationality.
The Taliban issued a statement on the deaths in Sangin district saying an Afghan soldier shot and killed the service members on their base and then defected to the insurgency. The Taliban said the dead coalition members were Americans and put the number killed at three, but often exaggerates casualty figures in announcing its attacks.
Taliban spokesman Qari Yousef said in the statement that the Afghan solider killed the coalition troops and then joined up with insurgents who took him to a safe place, according to a translation by the U.S.-based SITE Intelligence Group, which monitors militant forums.
NATO troops share bases with Afghan soldiers and conduct joint patrols. The close relationship is necessary to support Afghan forces as they carry out more operations, but leaves coalition forces vulnerable to attack by infiltrators.
On July 21, an Afghan army sergeant got into an argument at a shooting range in northern Afghanistan and fatally shot two American civilian trainers before being killed. Another Afghan soldier was killed in the crossfire. In a July 13 attack, an Afghan soldier stationed in the south killed three British troops, including the company commander.
In November 2009, an Afghan policeman killed five British soldiers in the south. A month earlier, an Afghan policeman on patrol with U.S. soldiers fired on the Americans, killing two.
NATO troops have also killed Afghan security forces. In August, a NATO helicopter mistakenly killed three Afghan policemen who had called in air support.
In July, a botched airstrike killed six Afghan soldiers in eastern Ghazni province after the unit gave a wrong location to international forces.