Chad's President Idriss Deby issued a warning to Boko Haram leader, Abubakar Shekau - surrender or be killed in battle.

"‎Abubakar Shekau must surrender. We know where he is. If he doesn't give himself up he will suffer the same fate as his compatriots," Deby warned in an article by Reuters.

Chad is one of the five nations in the Lake Chad Basin that committed to the formation of an 8,000 strong multinational task force to combat the threat of Boko Haram, which waged a sustained six-year insurgency primarily in northeastern Nigeria before carrying out cross-border attacks in Cameroon, Niger and Chad in the past few months.

The other nations in the joint task force are Cameroon, Niger, Nigeria and its western neighbour, Benin.

Chad's forces have seen consistent success in the ongoing allied offensive. Last month, Chadian soldiers expelled the militants from the northeastern Nigerian town of Gambaru. Reuters reported on Tuesday that Chad's military had pushed the Islamist fighters out of the town of Dikwa, also in the northeastern part of Nigeria.

Deby said that his soldiers spotted Shekau in Dikwa during the fighting.

"He was in Dikwa," Deby revealed to reporters following a regional meeting. "He managed to get away but we know where he is. It's in his interests to surrender," the Chadian president stressed.

Nigerian President Goodluck Jonathan made no comment about Deby's statement, although Nigerian forces have claimed on at least three occasions that Shekau has been in combat. 

The growing threat of Boko Haram has prompted the postponement of Nigeria's presidential elections out of fear that the militants will launch an attack on election day, rendering millions of Nigerian in the northeast unable to vote. It was rescheduled to March 28 in order to allow the multinational task force to secure northeastern Nigeria and neutralise the threat of the Islamist group.