Boko Haram has released 82 schoolgirls from a group of 276 they abducted in north-eastern Nigeria three years ago, President Muhammadu Buhari’s office says.
The girls were handed over in exchange for Boko Haram suspects after negotiations.
They will be received by President Muhammadu Buhari in Abuja on May 7, a statement said.
The abduction of the so-called “Chibok girls” triggered a global outcry and sparked a huge social media campaign.
The number of Boko Haram suspects released by authorities remains undisclosed.
Christian pastor Enoch Mark, whose two daughters were among those kidnapped, told AFP: “This is good news to us. We have been waiting for this day. We hope the remaining girls will soon be released.”
It was unclear whether his daughters had been freed.
A statement from a spokesman for President Muhammadu Buhari said he was deeply grateful to “security agencies, the military, the Government of Switzerland, the International Committee of the Red Cross, and local and international NGOs” for playing a role in the operation.
After the Government Girls Secondary School in Chibok, Borno state, was raided in April 2014, more than 50 girls quickly escaped and Boko Haram then freed another 21 in October 2016, after negotiations with the Red Cross.
The campaign for the return of the girls drew the support of then First Lady Michelle Obama and many Hollywood stars.
Last month, President Muhammadu Buhari said the Nigerian government remained “in constant touch through negotiations, through local intelligence to secure the release of the remaining girls and other abducted persons unharmed”.
Many of the Chibok girls were Christian, but were encouraged to convert to Islam and to marry their kidnappers during their time in captivity.
Boko Haram has kidnapped thousands of other people during its 8-year insurgency aimed at creating an Islamic caliphate in north-eastern Nigeria.
More than 30,000 others have been killed, the government says, and hundreds of thousands have been forced to flee from their homes.