Attackers in north-eastern Nigeria have killed three South Korean doctors, beheading one in the assault, according to officials.
The attack happened last night in Potiskum, a town in Yobe state. Officials said that the doctors worked at the General Hospital in Potiskum.
An Associated Press journalist saw the dead in the hospital morgue. One had been beheaded in the attack.
The three routinely travelled alone and without security guards in the city, which has been a repeated target of a radical Islamic sect known as Boko Haram. A Nigerian police official confirmed the attack took place, but declined to immediately comment further.