The reason for delay in release of more Chibok girls

Vice President Yemi Osinbajo has confirmed negotiations are ongoing for the release of more Chibok schoolgirls still in the custody of the Boko Haram terrorists.
Osinbajo said this on Tuesday evening at an interaction with journalists and activists at the state house in Abuja.
“There is a lot of negotiation going on,” he said.
He did not provide details of the negotiations for apparent security reasons, though.
The vice president added that one of the challenges the authorities are facing was the rivalry between the two factions in Boko-Haram.
One of the factions is led by Abubakar Shekau, the erstwhile leader of the group, while a breakaway faction is led by Abu Musab al-Barnawi, believed to be a son of the late founder of the group, Mohammed Yusuf.
Osinbajo, however, said the Buhari administration was very committed to the release of the remaining Chibok girls and other captives held by the Boko Haram.
Boko Haram abducted no fewer than 276 pupils from the Government Girls Secondary School in Chibok on the night of April 14, 2014. About 57 of the girls managed to escape in the immediate aftermath of the abduction.
Negotiations between the federal government and the terrorist group had led to the release of 21 of the girls while another three were freed by soldiers.
About 2,000 teenagers have been reportedly abducted by Boko Haram since 2014, with many of the women used as sex slaves, fighters and even suicide bombers, according to Amnesty International, the London-based human rights organization.
According to the United Nations Children Fund, UNICEF, said that at least 27 teenage girls have been used as suicide bombers in Borno within the first quarter of 2017.