A man claiming to be Boko Haram's leader has said he'll sell the more than 200 girls that the Islamist militant group abducted from all-girls school in Chibok, Borno state last month.

"I abducted your girls. I will sell them in the market, by Allah," a man claiming to be Abubakar Shekau says in a video, according to a CNN translation from the local Hausa language. "There is a market for selling humans. Allah says I should sell. He commands me to sell. I will sell women. I sell women."

The nearly hourlong video, first obtained Monday by Agence France-Presse, appears to be Boko Haram's first public confirmation that it abducted the girls on April 14 in northeastern Nigeria's restive Borno state.

According to accounts, armed members of Boko Haram overwhelmed security guards at the all-girls school in Chibok, pulled the girls out of bed and forced them into trucks. The convoy of trucks then disappeared into the dense forest bordering Cameroon.

On Friday, Nigerian authorities updated the number of girls kidnapped to 276. At least 53 of the girls escaped, leaving 223 in the hands of their captors, police said.

Authorities said the number of missing girls could grow as police fill in spotty school enrollment records.