Updated: 6:03 p.m. | Every female senator signed a letter to President Barack Obama Tuesday, calling for international sanctions against the terrorist group that abducted more than 200 girls in Nigeria last month.  

Sens. Barbara A. Mikulski, D-Md., and Susan Collins, R-Maine, led the group of women pressuring the administration to implore the U.N. Security Council to add Boko Haram to its al-Qaida sanctions list.  The Islamist militant group claimed responsibility for the kidnappings Monday.  

“In the face of the brazen nature of this horrific attack, the international community must impose further sanctions on this terrorist organization,” the senators wrote. “Boko Haram is a threat to innocent civilians in Nigeria, to regional security, and to U.S. national interests.” The girls were abducted from the government secondary school in Chibok, Nigeria, in mid-April and Boko Haram has threatened to sell the girls into slavery.  

“The girls were targeted by Boko Haram simply because they wanted to go to school and pursue knowledge,” wrote the female senators, “and we believe the United States must respond quickly and definitively.”  

The Senate passed a resolution by voice vote on Tuesday afternoon condemning the kidnapping.  

“We’ll do everything we possibly can to get them home to their families,” Sen. Barbara Boxer, D-Calif., said on the Senate floor.  

Mikulski also addressed the Senate floor after the body adopted the resolution and said, “The women of the Senate are going to be meeting with Secretary [of State John] Kerry and I believe this is an issue worthy of our attention, worthy of our time and worthy of our vote.”  

President Obama commented on the situation Tuesday, calling the kidnapping a “heartbreaking situation, an outrageous situation” in an interview with ABC News. The president’s comments follow his administration’s announcement earlier in the day that it will send a team of experts to Nigeria to help search for the missing girls.  

The president did not say what other actions the U.S. was willing to take in Nigeria, but described the team being sent to the African nation. “We’ve already sent in a team to Nigeria,” said the president. “They’ve accepted our help through a combination of military, law enforcement, and other agencies who are going in, trying to identify where in fact these girls might be and provide them help.”  

Obama also said the kidnapping could ignite an international backlash against Boko Haram. “This may be the event that helps to mobilize the entire international community to finally do something against this horrendous organization that’s perpetrated such a terrible crime,” said the president.  

Mikulski said the senators were “heartened” by this development, but called on the international community to send the message: “Leave girls and boys alone!”