The somber faces of roughly 50 kidnapped girls appear in a new video released by militant group Boko Haram. They are believed to comprise some of the Chibok schoolchildren kidnapped over two years ago, in April 2014.

The masked militant in the video—still unidentified—declares that the girls will only be freed if the Nigerian government hands over the members of Boko Haram currently held prisoner.

In the video, one young woman issues a collective address to the families of the kidnapped schoolgirls. As the Guardian reports, she identifies herself as Maida Yakubu.

“To our parents — please be patient. There is no kind of suffering we haven’t seen. Our sisters are injured, some of them have wounds on their heads and bodies. Tell the government to give [Boko Haram] their people, so we can come home to you.

We are all children. We don’t know what to do. The suffering is too much. Please try. We have been patient. The only thing that can be done is to give them their people so we can go home.”

The fighter in the video emphasizes to the Chibok parents that “their children are still in our hands.” And he warns that if Nigerian president Muhammadu Buhari sends troops on a rescue mission, the girls will be slaughtered. And no alternative negotiations will be accepted.

“Don’t waste time,” the masked fighter says, “released our members in custody, and we will release the girls.”

Boko Haram takes issue with the government airstrikes targeting their camps. These attacks have been part of Buhari’s efforts, since he came to power in May 2015, to neutralize Boko Haram. But while he swore to prevail in the course of a year, the militants have continued to murder, rape, and kidnap thousands of East Nigerians. Hundreds have been killed by suicide bombings.

Two hundred seventy-six girls were originally kidnapped from their dormitories at gunpoint, and 217 are missing still. The anonymous Boko Haram member claims that 40 of the girls have been forced to marry and that others have been killed by the government airstrikes. The video purports to show footage of their bodies in the aftermath, but their cause of death remains a point of contention among analysts. Some argue that the girls’ wounds could only have been inflicted by machetes.

In such dire circumstances, there is only meager comfort to be had — that the girls who appear in the video are still alive. Yakubu’s father, Dorcas Yakubu tells CNN, “I’m very, very happy I saw my daughter on the video, and I’m very happy she’s alive. Some people has said the kidnapping is not true. Some people have said they are no more alive. Now I see her, and I know she’s ok.”

Immediately after the kidnapping, First Lady Michelle Obama initiated the #BringBackOurGirls campaign via hashtag launch. And yet Boko Haram still flaunts their custody of the schoolgirls and emphasizes their perilous circumstances. It’s not clear how the Nigerian government will proceed in order to both protect and rescue the Chibok schoolgirls.