History of Chad Africa's major language groupings south of the Sahara Desert (except Khoisan, which is not considered a valid genetic grouping anyway), i. e. the Afro-Asiatic, Nilo-Saharan and Niger–Congo phyla, originated in prehistoric times in a narrow band between Lake Chad and the Nile Valley. The origins of Chad's peoples, however, remain unclear. Several of the proven archaeological sites have been only partially studied, and other sites of great potential have yet to be mapped. At the end of the 1st millennium AD, the formation of states began across central Chad in the sahelian zone between the desert and the savanna. For
Boko Haram towards them a higher level of international attention. The U.S. Bureau of Counterterrorism provides the following summary of Boko Haram's 2013 foreign operations: Boko Haram has often managed to evade the Nigerian army by retreating into the hills around the border with Cameroon, whose army is apparently unwilling to confront them. Nigeria, Chad and Niger had formed a Multinational Joint Task Force in 1998. In February 2012, Cameroon signed an agreement with Nigeria to establish a Joint Trans-Border Security Committee, which was inaugurated in November 2013, when Cameroon announced plans to conduct "coordinated but separate" border patrols in 2014. It