The liberation of the so-called "Chibok girls" — whose abduction triggered the #BringBackOurGirls campaign — came after negotiations between the government and Boko Haram, said Mallam Garba Shehu, a Nigerian government spokesman.
Shehu didn't say what Boko Haram received in return, but the BBC reported that the government handed over four imprisoned militants as part of the deal. The negotiations were brokered by the Swiss government and the International Committee of the Red Cross.
The release was the first in what is hoped to be a series of releases over the coming weeks. After last week's release, 197 girls are believed to remain in the hands of Boko Haram; the government says negotiations for their freedom are continuing.
Alex Johnson is a reporter and editor for NBC News based in Los Angeles.