Nigeria's new President Muhammadu Buhari praised Chad for joining the fight against Boko Haram terrorist group.

He said further cooperation was essential in the future.

He met with Chad's President Idriss Deby in the capital, N'Djamena, after a visit Wednesday to Niger.

Buhari, who took office last Friday, has made ending the Boko Haram insurgency a priority, after six years of violence that has left at least 15,000 people dead.

"Your troops have stood shoulder to shoulder and fought gallantly with ours in the fight against the forces of evil," he told Deby.

"This is a remarkable show of good neighborliness, which we must reinforce in the years ahead."

Deby for his part "reaffirmed Chad's involvement and availability" to work with Nigeria, according to a statement from his office.