The girls were taken from a school in the town of Chibok, in northern Nigeria, three weeks ago.
Yesterday, an extremist Nigerian insurgent leader boasted that he had kidnapped the school girls in a video released to Agence France-Presse.
In the video, the man claiming to be Boko Haram leader Abubakar Shekau, says: “I abducted your girls. I will sell them in the market, by Allah … There is a market for selling humans. Allah says I should sell. He commands me to sell. I will sell women. I sell women.”