The deadly Boko Haram group released a new video on Sunday showing of kidnapped Chibok schoolgirls whose fighters claimed were killed by Nigerian airstrikes.

A masked, camouflaged fighter who appeared in the 11½-minute video said many of the schoolgirls had died in the strikes, according to the SITE Intelligence Group, which monitors militant jihadist groups. The unidentified fighter also demanded the release of imprisoned militants in exchange for the release of the girls.

No immediate comment from the government or the military concerning the video, apart from what President Muhammadu Buhari said last year that he was open to negotiating with the group.