THE US says it is “outraged” by the kidnapping of more than 200 Nigerian school girls by Islamist militants and has vowed to help rescue them.
White House spokesman Jay Carney said President Barack Obama was being briefed and his national security team was monitoring developments.
The Boko Haram militants released a video claiming to have the girls, who were taken from their school in Chibok, in Nigeria's northeast.
The group’s leader Abubakar Shekau threatened to sell the girls, saying they would put the teenagers “in the market, by Allah”.
America’s pledge follows a series of social media campaigns and street protests outside in London to pressure the Nigerian government and the international community into taking action.
On May 3, demonstrators outside the Nigerian embassy waved banners saying "bring back our girls" and chanted "free our sisters".
The protesters held a two minutes silence to criticize the Nigerian government's handling of the rescue effort and urge the British government to lend their support.
Stella Creasy, MP for Walthamstow, who was also at the demonstration, pledged to take up the issue with foreign secretary William Hague.
In the US, six senators have introduced a resolution supporting the Nigerian people and calling for the immediate return of the girls.
Senator Dick Durbin, one of the resolution's sponsors, called the kidnapping "an affront to the civilised world".
He tweeted: "We and our African allies should do everything to help the Nigerian government rescue innocent girls and return them to their families.”
In an address to the US Senate, Democrat senator Amy Klobuchar also called for action.
"We cannot close our eyes to the clear evidence of barbarity unfolding before us in Nigeria," she said.
"This is one of those times when our action or inaction will be felt not just by those schoolgirls being held captive and their families waiting in agony, but by victims and perpetrators of trafficking around the world. Now is the time to act."