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)

Women displaced as a result of Boko Haram attacks in the northeast region of Nigeria, sit together at a camp for internally displaced people in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

Children, who have fled Boko Haram violence in the northeast region of Nigeria, take part in aerobic exercises at Maikohi secondary school at the camp for internally displaced people (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, attend class at Maikohi secondary school inside a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, clap during a class at Maikohi secondary school camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

People fleeing Boko Haram violence in the northeast region of Nigeria, cook food at Maikohi secondary school camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

A boy displaced as a result of Boko Haram attack in the northeast region of Nigeria, poses for a picture at Maikohi secondary school camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

Children displaced as a result of Boko Haram attack in the northeast region of Nigeria, attend a class at Maikohi secondary school camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

A girl displaced as a result of Boko Haram attack in the northeast region of Nigeria, rests her head on a desk at Maikohi secondary school camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

A displaced mother and her daughters, who fled Boko Haram violence in the northeast region of Nigeria, sit together at Maikohi secondary school camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, sell sundry goods at a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, sit in a row to eat a meal at a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

A man displaced as a result of Boko Haram attacks in the northeast region of Nigeria, helps his son do up the buttons on his shirt at a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

A traditional hunter, one of a militia group helping the army to fight the Boko Haram insurgence, poses for a photograph in Yola, Adamawa State January 14, 2015. (Photo by Afolabi Sotunde/Reuters)

Children displaced as a result of Boko Haram attacks in the northeast region of Nigeria, cheer at a camp for internally displaced persons (IDP) in Yola, Adamawa State January 13, 2015. (Photo by Afolabi Sotunde/Reuters)

A leader of militia hunters helping the army to fight the Boko Haram insurgence in the northeast region of Nigeria, holds a magazine of bullets in his hands during an interview in Yola, Adamawa State January 14, 2015. (Photo by Afolabi Sotunde/Reuters)

Militia hunters helping the army to fight the Boko Haram insurgence hold a meeting in Yola, Adamawa State January 14, 2015. (Photo by Afolabi Sotunde/Reuters)

People displaced as a result of Boko Haram attacks in the northeast region of Nigeria, are seen near their tents at a faith-based camp for internally displaced people (IDP) in Yola, Adamawa State January 14, 2015. (Photo by Afolabi Sotunde/Reuters)

Baby Lurky, whose family was displaced as a result of Boko Haram attacks in the northeast region of Nigeria, sleeps in the shade at a camp for internally displaced people (IDP) in Yola, Adamawa State January 14, 2015. (Photo by Afolabi Sotunde/Reuters)

Women displaced as a result of Boko Haram attacks in the northeast region of Nigeria, spend the time fixing their hair at a camp for internally displaced people in Yola, Adamawa State January 14, 2015. (Photo by Afolabi Sotunde/Reuters)

A woman displaced as a result of Boko Haram attacks in the northeast region of Nigeria, poses for a picture next to a sign showing the weekly programme of a church at a camp for internally displaced people in Yola, Adamawa State January 14, 2015. (Photo by Afolabi Sotunde/Reuters)

A girl displaced as a result of Boko Haram attacks in the northeast region of Nigeria, uses a mortar and pestle at a camp for internally displaced people in Yola, Adamawa State January 14, 2015. (Photo by Afolabi Sotunde/Reuters)

A young woman refugee from Nigeria looks through a fence in Ngouboua, January 19, 2015. Refugees fleeing attacks by Islamist militant group Boko Haram continued to cross the border into neighbouring Chad on Monday. According to United Nations and government figures, some 20,000 Nigerians had fled to Chad, Niger and Cameroon in the two weeks prior to January 13 after their towns and villages were attacked. (Photo by Emmanuel Braun/Reuters)

Men on camels cross the water as a woman washes clothes in Lake Chad in Ngouboua, January 19, 2015. (Photo by Emmanuel Braun/Reuters)

Women who have fled violence in Nigeria queue for food at a refugee welcoming center in Ngouboua, Chad, January 19, 2015. (Photo by Emmanuel Braun/Reuters)

Men who have fled violence in Nigeria sit on the ground at a refugee welcoming center in Ngouboua, Chad, January 19, 2015. (Photo by Emmanuel Braun/Reuters)