Nigeria's President Mohammed Bukhari said Thursday that his country will cooperate with its neighbors to fight extremism, Al-Bawaba News cited Fox News as said. Bukhari's remarks came after his 2-day visit to Cameroon where he held negotiations with his Cameroonian counterpart, Paul Biya focusing on the threat posed by Nigerian Boko Haram extremists. "No one of us can single-handedly success in the war against Boko Haram," Bukhari said. Nigeria, Cameroon, Niger and Chad had formed a joint forces in March 2015 to confront the extremist group.