Twenty-one of the schoolgirls kidnapped in 2014 by Boko Haram in Chibok, Nigeria, have been freed, the president's spokesman has confirmed.
Garba Shehu said the release was "the outcome of negotiations between the administration and Islamist militants".
Four imprisoned militants were reportedly freed in exchange.
Boko Haram seized more than 270 students from a school in Chibok, north-east Nigeria - an act that provoked international condemnation.