As many as 100 of the 270 Chibok girls abducted from their school in April 2014 are still believed to be held captive by Boko Haram.
Two of the so-called Chibok girls, abducted by Boko Haram in 2014, recently visited Trump at the White House.
The girls were among the 276 abducted by Boko Haram in April 2014. More than 100 remain in the militants' hands.
The Sultan of Sokoto said that the almajiri system, where children beg to fund an education in the Koran, was not part of Islam.
83 of the girls were to be released in a prisoner swap, but one said she was "happy" in Boko Haram captivity.
Boko Haram released 82 more girls, but global scrutiny and a long rehabilitation program means freedom may yet prove elusive.
Muhammadu Buhari spent nearly two months in London for treatment for an unknown condition earlier in 2017.
The kidnapping was one of the high-profile incidents of Boko Haram's insurgency, now in its eighth year and with little sign of ending. About 220 were abducted from their school in a night-time attack.
Despite help from the U.S., two successive Nigerian presidents have failed to liberate the vast majority of girls captured by Boko Haram.
A report alleged that the U.K. offered to rescue the girls, but Jonathan declined.
The protests went ahead despite a star singer dropping out.
The girls are studying at the American University of Nigeria in Yola.
More than two years on, 196 Chibok girls remain missing.
The kidnapping of women and girls is just one sign of a lack of gender equality in Nigeria
The ISIS-allied faction of Boko Haram is reportedly holding a large group of the girls.
The Nigerian government said the released girls were in state custody.
The Nigerian military said it had "fatally wounded" Shekau in August.
Ahmad Salkida was accused by the Nigerian military of concealing information about the whereabouts of the Chibok girls.
The Nigerian military is planning a large offensive on the group's final stronghold in the near future.
Amina Ali Nkeki escaped in May and fathered a child by a suspected Boko Haram member.
The militant group's latest video demanded the release of its fighters in exchange for the girls.
One of the Nigerian schoolgirls is used to plead with the federal government to release Boko Haram militants.
A purported ISIS magazine has designated Abu Musab al-Barnawi as the Nigerian group's new chief.
At least four villagers were killed in the attack Tuesday.
Girl says all but six of the Chibok girls are alive and being held in the Sambisa Forest, which contradicts the assumption the girls had been widely scattered.