A U.S. soldier in Afghanistan is believed to have killed at least three Afghan civilians after leaving his base in Kandahar province, the BBC reported.
Following the incident, the soldier surrendered to U.S. military authorities, the BBC said.
The soldier is believed to have suffered a mental breakdown, according to the BBC's Quentin Sommerville in Kabul.
The NATO-led International Security Assistance Force (ISAF) in Afghanistan confirmed in a statement on Sunday that a U.S. soldier has been detained in connection with an incident involving civilian casualties in Kandahar province, Reuters reported.
U.S. Forces-Afghanistan, in cooperation with Afghan authorities, will investigate this incident, ISAF said in the statement quoted by Reuters. This is a deeply regrettable incident and we extend our thoughts and concerns to the families involved. ISAF did not elaborate.
Kandahar Gov. Tooryalai Wisa told Reuters a U.S. soldier left his base in Kandahar on Saturday and opened fire on civilians. He said initial reports indicated as many as 16 civilians were killed. That could not be immediately confirmed.
NATO forces representative Justin Brockhoff confirmed a U.S. service member had been detained as the alleged shooter, but he did not provide details on the incident, according to The Associated Press. Brockhoff said the coalition had reports of multiple wounded -- but none killed - and that the wounded were receiving treatment at NATO medical facilities, AP reported.
Anti-American sentiment in Afghanistan had already been running high before reports of the latest civilian casualties because of the actions of some U.S. soldiers who burned copies of the Quran at a NATO base last month.