Washington - US experts assisting the search for the kidnapped Nigerian schoolgirls are closely examining a new video for clues to their whereabouts, American officials said on Monday.
"Our intelligence experts are combing through every detail of the video for clues that might help ongoing efforts to secure the release of the girls," state department spokesperson Jen Psaki said.
"We have no reason to question its authenticity," she added after AFP obtained a new video said to be of about 130 of the girls kidnapped last month by the Islamic militant Boko Haram group.
In the video, the group's leader Abubakar Shekau said the girls may be released once Nigeria frees all the Boko Haram prisoners it has in custody.
But that proposal has been rejected by the Nigerian government, and Psaki recalled that the US policy is also "to deny kidnappers the benefits of their criminal acts, including ransoms or concessions."
Psaki stressed however that the Nigerian authorities were "in the lead" during the investigation.
A US team arrived on the ground last week in Nigeria to help growing efforts to find more than 200 girls aged between 16 to 18, snatched from their boarding school in the northeast of the country on 14 April.