Members of the Abuja "Bring Back Our Girls" protest group sit during a march in continuation of the Global October movement. Once again, Boko Haram militants are implicated in killings and mass kidnapping in northeastern Nigeria. Afolabi Sotunde/Reuters/Landov hide caption

itoggle caption Afolabi Sotunde/Reuters/Landov

Civilians who had just recently arrived in Yola prepare to flee again, this time in a large open-top truck headed to the city of Jos. Ofeibea Quist-Arcton/NPR hide caption

itoggle caption Ofeibea Quist-Arcton/NPR

#BringBackOurGirls" campaigners participate in a lamentation parade in Abuja, in early November, as more towns in Nigeria come under attack from Boko Haram. Afolabi Sotunde/Reuters/Landov hide caption

itoggle caption Afolabi Sotunde/Reuters/Landov

Ramatu Usman, shown here with one of her sons, is a 37-year-old mother of eight. She says she was separated from one of her sons, 6-year-old Yahaya Buba, following an attack. He is still missing. Ofeibea Quist-Arcton/NPR hide caption

itoggle caption Ofeibea Quist-Arcton/NPR

People inspect the site of a suicide bomb explosion at the Government Science Technical College in Potiskum, Nigeria, Monday. Survivors say a bomber disguised in a school uniform detonated explosives during an assembly at the school. Adamu Adamu/AP hide caption

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People call for the Nigerian government to rescue girls taken from a secondary school in Chibok region, during a protest earlier this month. Boko Haram, the group that took the girls, says they have been "married off." Olamikan Gbemiga/AP hide caption

itoggle caption Olamikan Gbemiga/AP

A man poses with a sign in front of police officers in riot gear during a demonstration calling on the government to rescue the kidnapped girls of a government secondary school in Chibok, in Abuja, Nigeria, on Tuesday. Olamikan Gbemiga/AP hide caption

itoggle caption Olamikan Gbemiga/AP

Earlier this month, people demonstrated in Nigeria's capital, Abuja, calling on the government to rescue girls taken from a secondary school in Chibok region in April. Now there are reports that militants of the extremist Boko Haram movement have kidnapped more girls. Olamikan Gbemiga/AP hide caption

itoggle caption Olamikan Gbemiga/AP

This week, Pakistani activist Malala Yousafzai met with some of the girls who escaped Boko Haram's captivity. The Islamic extremist group gained attention in April when it kidnapped more than 200 girls from a school in northeastern Nigeria. Many girls are still missing. Olamikan Gbemiga/AP hide caption

itoggle caption Olamikan Gbemiga/AP

Nigeria's chief of defense staff Air Marshal Alex S. Badeh speaks during a demonstration in Abuja calling for the rescue of girls kidnapped from their school in Chibok. Badeh says the government knows where the girls are — but that a rescue attempt would endanger their lives. Gbenga Olamikan/AP hide caption

itoggle caption Gbenga Olamikan/AP