WASHINGTON -- Michelle Obama is delivering the president's weekly address this week.
The White House says she will focus the radio and Internet address on Mother's Day and the nearly 300 girls who remain missing after being kidnapped more than three weeks ago from their school in Nigeria by an Islamist extremist group whose leader has threatened to sell them.
The case has sparked international outrage. The U.S. and other nations are assisting the Nigerian government in its efforts to find the girls.
This week, Mrs. Obama tweeted a photo of herself in the White House holding a sign with the message "(hashtag) Bring Back Our Girls."
Mrs. Obama has joined President Barack Obama on past weekly addresses. Saturday's will be the first one she delivers alone.