Dozens of Chibok schoolchildren have been released by Boko Haram militants after spending more than three years in captivity.
The girls, who were abducted from a secondary school in the remote north eastern town of Chibok in 2014, were released after tense negotiations with the government, according to one official said.
A total of 82 children - who were among a group of about 220 who were initially kidnapped - were released on Saturday.
Five Boko Haram commanders were released in an exchange deal, a Nigerian government official said Sunday.
The girls are expected to meet with Nigerian President Muhammadu Buhari later on Sunday.
Their kidnap shocked the world and sparking a huge campaign with the slogan "Bring Back Our Girls", supported by then-US First Lady Michelle Obama and a list of celebrities.
For more than two years there was no sign of the Chibok schoolgirls but the discovery of one of the girls with a baby in May 2016 fuelled hopes for their safety, with a further two girls found in later months.
More than 20 were released in October in a deal brokered by Switzerland and the International Red Cross, while a handful of others have escaped or been rescued.
About 100 are still missing.