Boko Haram militants on Saturday released 82 schoolgirls they had kidnapped in April 2014. They were released in exchange for several prisoners, the number of which is unknown. Around 270 girls had been kidnapped that year.

President Muhammadu Buhari’s government said several security agencies, the Swiss government, Red Cross, the military, and several NGOs had been involved in the “lengthy negotiations”. The girls who were freed will be formally received in Buhari on Sunday, All Africa reported. They were released in the north eastern town of Chibok. This brings the total number of girls released to 106.

A campaign for the girls’ release had drawn massive attention after it had drawn the support of former United States First Lady Michelle Obama and other celebrities. The Islamist extremist group has kidnapped thousands of adults and children, though. It has displaced more than 2 million people and killed around 20,000 since it started out in 2002. In 2015, it was said to be the deadliest militant group in the world, according to a Global Terrorism Index.