Twenty-one of the schoolgirls captured in 2014 by Islamist militant group Boko Haram have been freed.
In 2014, Boko Haram kidnapped 270 girls from a school in Chibok, northeast Nigeria. It sparked the social media hashtag #BringBackOurGirls, which attracted international attention.
The news was announced on Twitter, a spokesman for Nigerian President Muhammadu Buhari saying the International Committee of the Red Cross and the Swiss government mediated talks with Boko Haram.
Negotiations are continuing to take place.
This is the first mass release of any of the girls taken in the 2014 kidnapping, with just under 200 remaining unaccounted for.
The release is "a result of the round-the-clock efforts by the administration to put a closure to the sad issue of the [kidnappings]", Nigerian information minister Alhaji Lai Mohammed told reporters in Abuja.
Terms of the release are not currently known, but it is understood no captured Boko Haram fighters were released in return.