U.S. law enforcement officials said today that the FBI is standing ready for a possible deployment to Nigeria to help find the 276 teenage girls abducted from a school, but that no help had yet been requested.

Related: Who are the kidnapped Nigerian girls?

"Last week, the attorney general told U.S. intelligence agencies to prepare a report for him on the kidnapping of the 300 girls in Nigeria and also requested an assessment of Boko Haram, the militant group behind the kidnapping," a government official told ABC News.

As many as 300 girls, ages 16 to 18, were taken from their dormitories at the Government Girls Secondary School in Chibok, Nigeria, on April 15, according to the Associated Press. The students had been studying for final exams at their local school.

Police said that about 53 had escaped but as many as 276 remained in captivity. The leader of Boko Haram claimed responsibility today for the kidnapping and said he intended to sell the girls in the marketplace, according to a video obtained by the news agency AFP.

Related: What you need to know now about the kidnapped Nigerian girls.

"Many people come to our house, during the day, to sympathize with us," one mother of a missing girl told the BBC, "but then at night, our family stays awake all night, thinking of our daughter and all the other girls and what they're going through and where they're being held."

U.S. Secretary of State John Kerry said this weekend that Washington would "do everything possible" to support the Nigerian government return the girls to their homes.

School pupils hold signs as members of Lagos based civil society groups hold rally calling for the release of missing Chibok school girls at the state government house, in Lagos, Nigeria, May 5, 2014. (Pius Utomi Ekpei/AFP/Getty Images)

State Department deputy spokeswoman Marie Harf said today that the U.S. was sending a senior State Department official to Nigeria "in the coming days" to discuss the kidnapping of the schoolgirls and other security issues in Nigeria.

Harf would not go into specifics of how the U.S. was assisting Nigeria to do "everything possible" to find the girls as Kerry said this weekend, but she did say that the U.S. continued its counter-terrorism support to Nigeria

"Our counter-terrorism assistance to Nigeria focuses on intelligence and information sharing, a huge part of it, and also improving their own forensics and investigative capacities," said Harf. "Obviously these are all things that will be helpful as they try to find these girls who, as we have many indications, many of them have likely been moved out of the country to neighboring countries at this point."

The Nigerian government has demanded the girls' safe return. President Goodluck Jonathan promised today that they'd be returned, but Sarah Margon of Human Rights Watch said Nigerians did not feel like they could rely on the government for protection.

Related: Boko Haram: Kidnappers, slave-owners, terrorist and killers.

"Nigeria isn't quite sure how to handle Boko Haram," Margon said. "Going after Boko Haram in a militaristic way could end up getting the girls killed if they've got them in the same space, which would be … as atrocious as having been kidnapped."

ABC News' Colleen Curry, Dana Hughes, Pierre Thomas, Jack Date and Aaron Katersky contributed to this report.