The summit will look at ways to strengthen the multi-national force set up regional states to fight the militants, Mr Buhari's office said in a statement.

President Buhari visited troops on the front line on WednesdayImage caption: President Buhari visited troops on the front line on Wednesday

The presidents of Chad, Cameroon, Niger, the Central African Republic (CAR) and Benin are expected to attend the meeting in Chad's capital, N'Djamena.

The militants have killed about 40 soldiers and abducted more than 50 civilians in north-eastern Nigeria, and seized at least 15 children in neighbouring Niger in the last two weeks.