President Muhammadu Buhari on Sunday met with the 82 Chibok girls before his departure to London for another medical checkup. Neither Nigeria's government nor Boko Haram, which has links to the Islamic State group, gave details about the exchange.
But according to lawyer Zannah Mustapha, who has acted as a mediator between the Nigerian government and the extremists, some of the girls rejected the opportunity to return home.
"Many of the parents of the girls are anxious about the identities of the girls", said Maina Mohammed, uncle of one of the abducted girls.
"They will face a long and hard process to rebuild their lives after the indescribable horror and trauma they have suffered at the hands of Boko Haram", said Pernille Ironside, acting representative of UNICEF Nigeria.
Also, now that the girls have been freed, the same amount of efforts put into securing their freedom must be put into rehabilitating them and integrating them back into society.
"The Federal Government will like to commend the Security Agencies, the Red Cross, local authorities, local and foreign NGOs and all those who contributed in one way or another to secure the release of our Chibok Girls". Amnesty International has recorded 41 cases of mass abductions in the last three years.
"UNICEF is committed to doing whatever it takes, as long as it takes, to help these children recover a sense of normalcy with our available resources", Ironside added.
They are now with government officials in Nigeria's capital Abuja, where they will be rehabilitated before returning to their parents, many of whom do not know whether their daughters are among those freed.
"We urge the president and his government to earnestly pursue the release of all our Chibok girls and other abducted citizens of Nigeria", the group said in a statement.
"It therefore would have been better to ensure the release of all the girls at once".
Buhari late a year ago announced Boko Haram had been "crushed", but the group continues to carry out attacks in northern Nigeria and neighboring countries.
"A lot of factors come into play when a nation has to decide whether or not to engage in prisoner-hostage swap", he said. Others did not want to come home because they'd been radicalized by their captors, they said.
A Nigerian government official says that five Boko Haram commanders have been released in exchange for the 82 Chibok girls.
The faction in a statement by its spokesperson, Dayo Adeyeye said the release of the suspected terrorists is a setback in the War against insurgency.