Uknown

Three North Korean doctors have been killed in the north-eastern Nigerian state of Yobe. They were killed during the night in the town of Potiskum. Two of them had their throats slit while the third was beheaded.  The victims had been working at a government-run hospital. No-one knows who is behind the accident but it  happened in an area where the Islamist militant group, Boko Haram, has been active in recent years. More than 600 people were believed to have been killed in 2012 by the group, which is fighting to overthrow the government and create an Islamic state in Nigeria's predominantly Muslim north. Yobe state police commissioner Sanusi Rufai said it was nevertheless too early to know who was behind the attack, which happened either late on Saturday or before dawn on Sunday. Police have begun an investigation.