The White House said the United States is doing what it can to help find and free nearly 300 Nigerian girls kidnapped by Islamic extremists.
White House spokesperson Jay Carney called the mass abduction from a school "an outrage and a terrible tragedy."
"The State Department has been in regular touch with the Nigerian government about what we might do to help support its efforts to find and free these young women," Carney said.
He said US assistance includes counter-terrorism support and logistics to Nigerian investigators.
The leader of militant Islamist organisation Boko Haram says he is keeping the girls as slaves and is threatening to sell them.
The Nigerian military has flown more than 300 sorties in the hunt for the abducted schoolgirls, a Major has told ITV News' Rageh Omaar.
A newly released video from Boko Haram reportedly shows the kidnapped Nigerian schoolgirls.
The man who started a viral hashtag campaign in support of the kidnapped Nigerian schoolgirls says it has forced the government to act.