More than 200 girls remain missing despite Buhari's claim that Boko Haram had been "technically" defeated.
Children face abduction and conscription by the extremist group, which has killed an estimated 1,000 people this year.
Boko Haram militants took control of Mubi in Adamawa State on Oct. 28, killing dozens of people. Now, it's been retaken.
Negotiations between Nigeria and Islamist militant group Boko Haram to secure release of abducted girls have not been jeopardised by a surge in violence, claims foreign minister
Nigeria's military announced a ceasefire 10 days ago ahead of the negotiations, but since then bombings, killings and kidnappings have continued.
Nigeria's military has reportedly agreed a truce with Boko Haram, in a deal that may also see the release of 200 schoolgirls taken hostage by the Islamist group
Boko Haram kidnapped nearly 300 young women six months ago. Most are still missing
"She was found running in a village. She was in the bush for about four days. She's still receiving medical attention," said a parent