The continued disappearance of hundreds of kidnapped Nigerian girls is sparking global public outrage.
Here's what you need to know about the mass abduction:
On April 15, more than 300 teenage schoolgirls were abducted from the Chibok Government Girls Secondary School in northeast Nigeria. Since then, at least 53 girls are known to have escaped.
Who did it?
Boko Haram — which means "western education is a sin" — is an Islamic militant group in Nigeria. The group's leader, Abubakar Shekau, is taking responsibility for the mass abduction, according to a video obtained by Agence France-Presse.
In the video, Shekau described the girls as slaves and said, "By Allah, I will sell them in the marketplace."
Unconfirmed reports last week said the girls were being sold as brides for $12 each.
Where are the girls now?
Authorities still don't know.
What's the Nigerian government's response?
The Nigerian government said the release of the videotape won't deter efforts to rescue the girls.
But a government spokesman also criticized the girls' parents for not fully cooperating with police, according to comments by Doyin Okupe, spokesman for President Goodluck Jonathan, to CNN.
What's the public's response?
The continued search for the girls has increased the calls for more action from the Nigerian government. More than 280,000 have signed a Change.org petition calling for the girls to be returned. On Twitter, users are using the hashtag #BringBackOurGirls.
On #bringbackourgirls. Another example that hashtag activism can generate attention. Everything else after that gets complex, very quickly.— Zeynep Tufekci (@zeynep) May 6, 2014
Crowds have rallied for the girls from Lagos to London to Los Angeles. In Washington, D.C., people are rallying
What's the U.S. government's response?
The U.S. State Department has been briefed "several times" about the situation, and the U.S. government has offered counterterrorism help, said White House spokesman Jay Carney, the BBC reports. Also, six senators have introduced a resolution calling for the immediate return of the girls.
Contributing: The Associated Press.