Officials say that clashes between a joint Turkish-Iraqi force and Islamic State militants near a training camp outside the northern Iraqi city of Mosul have left at least 18 IS fighters dead.

The fighting erupted late on Thursday outside the Bashiqa camp, which was at the center of a controversy last month when Turkey moved troops there to protect Turkish trainers aiding local Sunni fighters hoping to take back Mosul from the Islamic State group.

Baghdad has demanded that Turkish troops withdraw, describing their presence as a violation of international law. Ankara has pulled some troops out but not all.

Turkish President Erdogan said on Friday that IS tried to infiltrate Bashiqa, triggering the clashes. Former Iraqi governor Atheel al-Nujaifi, who founded the training camp, said the attack was repelled.