The Nigerian government has already rejected a Boko Haram proposal to free the girls in return for the release of the militant group’s prisoners. Boko Haram leader Abubakar Shekau floated the offer in a video on Monday.

Abubakar Shekau: “By Allah, these girls will not leave our hands until you release our brothers in your prison. You took our brothers four or five years ago, and now they are in your prisons. You do many things, and now you talk of these girls. We will not let them go until you release our brothers. We will not let them go until you release our brothers.”

The Boko Haram’s video showed close to half of the nearly 300 missing girls. It was the first public image of the kidnapped schoolgirls since their abduction nearly one month ago.