Boko Haram militants have released 82 schoolgirls -- out of a group of more than 200 kidnapped from the northeastern town of Chibok in April 2014 -- in exchange for prisoners, the presidency said Saturday.

Switzerland and the International Committee of the Red Cross helped secure the 82 girls in "lengthy negotiations," the presidency said on its Twitter account.

President Muhammadu Buhari was to receive the girls Sunday in the capital, Abuja, it said, without saying how many Boko Haram suspects were exchanged or disclosing other details.