A man believed to be an Afghan Border Police officer killed six U.S. troops Monday at a training facility in northeastern Afghanistan near the Pakistani border.
U.S. officials who declined to be identified confirmed that the six NATO troops killed in the incident were Americans.
A NATO statement says a gunman wearing an Afghan Border Police uniform turned his weapon on NATO troops during a training mission. The statement says the assailant was killed during the attack.
The Associated Press quoted Afghanistan's Interior Ministry as saying the gunman was a border police officer.
NATO has not confirmed the identity of the assailant and said a joint Afghan-ISAF team is investigating the incident.
In other violence Monday, two Afghan children were killed and another one wounded in a bomb blast in southern Kandahar province.
Meanwhile, NATO says joint NATO-Afghan security forces discovered several weapon caches in southern and eastern Afghanistan over the past 24 hours.
In eastern Ghazni province, a joint patrol discovered an abandoned compound with 1,500 kilograms of homemade explosives.
In southern Kandahar and Helmand provinces, forces found multiple rocket-propelled grenades, rifles and ammunition. All caches were securely destroyed.
Some information for this report was provided by AP and AFP.