Updated

A U.S. serviceman walked off his base in southern Afghanistan and opened fire on local civilians early Sunday morning, killing at least 16 people and wounding several more, according to Afghan officials.

The serviceman, who went on the shooting spree in a village about a mile away from the U.S. base in the Panjway district of Kandahar province, has since been taken into custody by U.S.-led coalition forces.

Hajji Agha Lalai, the Kandahar provincial council chief who visited the shooting's site Sunday, said the U.S. serviceman entered the village at about 1 a.m., and then went from house to house gunning down local men, women and children. In one of the compounds, Mr. Lalai and the visiting team of Afghan officials found a total of 11 bodies, all from the same family.

U.S. Air Force Captain Justin Brockhoff, a coalition spokesman in Kabul, confirmed numerous civilian casualties in the village and said the injured Afghans were being treated in coalition military facilities. A joint Afghan-coalition investigation was under way, Capt. Brockhoff added. At this point, he said, it wasn't clear what the shooter's motive was, and whether he has had previous contact with his victims.

Every effort will be made to establish the facts and to hold anyone responsible to account," British Army Lt. Adrian Bradshaw, the coalition's deputy commander, said in a statement that expressed "deep regrets and sorrow at this appalling incident." The U.S. Embassy in Kabul also condemned the shooting, promising that "the individual or individuals responsible for this act will be identified and brought to justice."

Sunday's incident is likely to ratchet up tensions between Washington and Kabul at a delicate moment for the two countries. U.S. and Afghan officials are in the midst of negotiating a long-term strategic partnership agreement that will lay out the framework for U.S. troop presence in the country after most foreign forces withdraw in 2014.

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