Boko Haram, the Islamist extremist group operating in rural areas of Nigeria have released 21 girls in exchange for four of their soldiers being held by that nation’s government, the BBC reported Thursday.

The schoolgirls, have been in captivity under the group since 2014, the government said. As many as 197 girls still remain with the extremists, but it unclear how many of them may have died since they were kidnapped.

The deal was brokered by the International Red Cross and the Nigerian government, according to Reuters. “It is the first step in what we believe will be the release of all the girls,” Information Minister Lai Mohammed said to reporters.

All but three of the schoolgirls were carrying babies, an aid worker who saw the girls in Maiduguri told The Associated Press. He spoke on condition of anonymity because he was not authorized to speak to the press. Many Boko Haram captives recently freed by military action have been shunned by their communities because they have come home pregnant or with babies from the fighters.
The group, which aligns itself with the Islamic State of Iraq and Syria (ISIS), kidnapped 270 girls from their school in Chibok, located in northeast Nigeria. More than 50 were able to escape on the day they were captured, the BBC said. In May, one of the girls, Amina Ali Nkeki, escaped on her own. Shortly after her release Nkeki told her family that some of the kidnapped girls died of illness and that others, like her, have been married to fighters and are pregnant or already have babies, her mother told the press.

Nigerian president Muhammadu Buhari said through a spokesman that negotiations were continuing to guarantee the safe return of the other girls.

The kidnapping spurred a global outcry over the girls’ abduction, buttressed by the social media hashtag #BringBackOurGirls. The movement released a statement Thursday morning about the development on Facebook.

“We take this opportunity to salute the work of our security services at the front lines – the commitment, resilience and tireless efforts of our members of the Multi-national Joint Task Force and the civilian JTF,” said leaders Aisha Yesufu and Oby Ezekwesili.

The group is blamed for as many as 30,000 deaths in Nigeria. Hundreds of thousands have become refugees because of Boko Haram attacks.  But the military has retaken much of the territory the extremists have taken since their formation in 2009.

With AP.