Three doctors have been killed in an attack in the north-eastern Nigerian state of Yobe, officials say.
Police commissioner Sanusi Rufai told the AFP news agency that armed men had entered the doctors' flat in the town of Potiskum and slit their throats.
The victims appear to have been foreign nationals. One report citing officials said they were South Korean while another said they were from China.
Potiskum has seen repeated attacks by Boko Haram.
No group has yet said it was behind the attack on the doctors, which reportedly happened either late on Saturday or before dawn on Sunday.
Local officials told the Associated Press that the victims had all worked at the General Hospital in Potiskum and that they routinely travelled through the town without security guards.