Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, run at a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. Boko Haram says it is building an Islamic state that will revive the glory days of northern Nigeria's medieval Muslim empires, but for those in its territory life is a litany of killings, kidnappings, hunger and economic collapse. (Photo by Afolabi Sotunde/Reuters)

An abandoned tank left by Boko Haram, February 20, 2016, seen on the road to Michika, Nigeria – a town formerly occupied by the insurgents. On April 14, 2014, 300 schoolgirls in the Chibok village in Nigeria were kidnapped by the terrorist group, Boko Haram. Two years later, the majority of these girls are still missing. According to the Global Terrorism Index Report 2015, Boko Haram, which operates mainly in Nigeria, has become the most deadly terrorist group in the world. (Photo by Danielle Villasana)

A man holds a cow at the cattle market in Maiduguri, Nigeria, March 9, 2016. A Nigerian government push to strangle the Boko Haram insurgency has shut down the cattle trade that sustained the city of Maiduguri, leaving many residents with no livelihood, including many of the two million people displaced by the war. In recent months the army has taken back much of the territory lost to the jihadists during the five-year insurgency. (Photo by Afolabi Sotunde/Reuters)

A girl walks past a destroyed mosque in the town of Mararaba, after the Nigerian military recaptured it from Boko Haram, in Adamawa state May 10, 2015. (Photo by Akintunde Akinleye/Reuters)

A child rescued from Boko Haram in Sambisa forest is seen at the Internally Displaced People's camp in Yola, Nigeria May 3, 2015. Hundreds of traumatised Nigerian women and children rescued from Boko Haram Islamists have been released into the care of authorities at a refugee camp in the eastern town of Yola, an army spokesman said. (Photo by Afolabi Sotunde/Reuters)