Michelle Obama has added her voice to calls for the safe return of nearly 300 kidnapped Nigerian schoolgirls. The US first lady posted a photo of herself in the White House holding a sign that says "#BringBackOurGirls". The tweet was signed "-mo," indicating that she sent it herself.

Mrs Obama is the latest high profile figure to join the campaign to rescue the girls who were abducted by Boko Haram, a Nigerian Islamist terror group.

Our prayers are with the missing Nigerian girls and their families. It's time to #BringBackOurGirls. -mo pic.twitter.com/glDKDotJRt

— First Lady- Archived (@FLOTUS44) May 7, 2014

#Malala stands in solidarity with Nigerians & people everywhere calling for action to #BringBackOurGirls pic.twitter.com/woAjreav0W

— Malala Fund (@MalalaFund) May 4, 2014

Shout! Participate! Show that you care! #BringBackOurGirls pic.twitter.com/ZBt7y7tXha

— AmyPoehlerSmartGirls (@smrtgrls) May 7, 2014

It's been two weeks since the kidnapping of 234 Nigerian girls and they still aren't home #bringbackourgirls pic.twitter.com/8OiC5GJPrc

— Mary J. Blige (@maryjblige) April 30, 2014

If 200 young girls had been kidnapped in Europe/America, the world would have acted by now. Get in there and get them. #BringBackOurGirls

— Piers Morgan (@piersmorgan) May 5, 2014

Its time 2 #BringBackOurGirls & put a stop 2 violence! Get info on how U can help —> http://t.co/ys5uItaNMy

— Queen Latifah (@IAMQUEENLATIFAH) May 7, 2014

Access to education is a basic right & an unconscionable reason to target innocent girls. We must stand up to terrorism. #BringBackOurGirls

— Hillary Clinton (@HillaryClinton) May 4, 2014

Together let's continue to raise awareness for the plight of the kidnapped Nigerian school girls #BringBackOurGirls pic.twitter.com/aaiKtE7Nhh

— Kelly Hoppen MBE (@kellyhoppen) May 8, 2014

Children are the reward of life. Rescue our Nigerian sisters. The world is watching, Make your voice heard. Retweet! #BringBackOurGirls

— Wyclef Jean (@wyclef) May 2, 2014

Are YOU with @KevinFrazier & @TheaAndrews? Tweet us YOUR #BringBackOurGirls photo & spread the word pic.twitter.com/T9QoCTohXG

— The Insider (@TheInsider) May 8, 2014
Boko Haram Nigeria