Boko Haram has appointed an Islamic cleric to negotiate on the terrorist organization's behalf for the release of the nearly 300 Nigerian schoolgirls it kidnapped in mid-April, sources close to the group told the Telegraph.

At the same time, the Nigerian officials said the government was open to negotiating with the group, saying it would “explore all options” to ensure the return of the girls.

“We are willing to carry that dialogue on any issue, including the girls kidnapped in Chibok, because certainly we are not going to say that [the abduction] is not an issue," Taminu Turaki, the Nigerian special duties minister, told AFP.

Boko Haram's leader demanded Monday in a video that the Nigerian government release terrorist prisoners in exchange for the girls, and the group is now preparing a list of militant names it wants released. The group reportedly wants one prisoner for each kidnapped girl.

In America, several senators have called for more action from the U.S., including sending special operations forces in to rescue the girls.

Sen. John McCain, R-Ariz., told the Washington Examiner's Susan Ferrechio that the U.S. government, once the girls are found, should send in U.S. troops to save the girls, even without permission from the Nigerian government, citing a United Nations bylaw.

“That gives any nation the license, if they can, to stop a crime against humanity,” McCain said. “It’s the same reason we should have, if we could have, gone in and freed people at Dachau or Auschwitz.”

During a press conference on Sunday, Sen. Chuck Schumer, D-N.Y., called for more action in the search for the missing girls.

"Imagine taking the flower of your nation, and trying to destroy it," Schumer said. He also called for the U.S. to provide its own reward for information leading to the girls’ return.

And earlier this month, Sen. Susan Collins, R-Maine, said during a CNN interview that U.S. troops should be sent in to retrieve the girls.

“More can be done by this administration. I would like to see Special Forces deployed to help rescue these young girls,” Collins said. “Some of these girls are as young as nine years old.”