US officials said they worried many of the girls seized three weeks ago had now been smuggled across Nigeria's borders into other countries, which could complicate already fruitless efforts to find them.
"We cannot close our eyes to the clear evidence of barbarity unfolding before us in Nigeria," said Democratic Senator Amy Klobuchar, her voice breaking as she addressed the Senate yesterday.
"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."
And the group's shadowy leader, Abubakar Shekau, threatened to sell them into slavery in a 57-minute video obtained by AFP that the State Department said appears "to be legitimate."
Also Read
There has been mounting anger and frustration in Nigeria at the failure of President Goodluck Jonathan's administration to find the girls aged 16 to 18, leading to protests on the streets.
"Some of the family members armed only with bows and arrows to fight terrorists armed with assault rifles rode into the forests on motorcycles to try to find their girls," said Klobuchar.
"We and our African allies should do everything to help the Nigerian government rescue innocent girls and return them to their families," Senator Dick Durbin, one of the resolution's sponsors, said in a tweet.
He called the Boko Haram kidnapping "an affront to the civilized world."
State Department deputy spokeswoman Marie Harf said Washington worries many of the girls have been moved out of the country, after local officials in northeastern Nigeria told AFP the girls had likely been taken to nearby Chad or Cameroon.
"We have many indications many of them have likely been moved out of the country to neighboring countries," Harf told reporters.
"We will continue working with" the Nigerian authorities, she added, refusing to outline specific US help.