BAUCHI, Nigeria - One of the teenagers who escaped from Islamic extremists who abducted more than 300 schoolgirls said Sunday the kidnapping was "too terrifying for words," and she is scared to go back to school.
Science student Sarah Lawan, 19, told The Associated Press that more of the girls could have escaped but that they were frightened by their captors' threats to shoot them.
Lawan spoke in the Hausa language in a phone interview from Chibok, her home and the site of the mass abduction in northeast Nigeria. The failure to rescue 276 of the students who remain captive four weeks later has attracted mounting national and international outrage.
"I am pained that my other colleagues could not summon the courage to run away with me," she said. "Now I cry each time I came across their parents and see how they weep when they see me."
Police say 53 students had escaped and captors are threatening to sell the students still held into slavery.
Lawan spoke as more experts are expected in Nigeria to help in the search, including U.S. hostage negotiators. Nigeria's government belatedly accepted offers of help last week from the United States, Britain, France, China and Spain.
Also Sunday, a leading Nigerian rights group demanded the U.N. Security Council impose sanctions on the Boko Haram terrorist network who abducted the girls, saying expressions of concern and condemnation are not enough.
"The future of these missing schoolgirls hangs in a balance. The council should not leave them to fend for themselves," executive director Adetokunbo Mumuni of the Socio-Economic Rights and Accountability Project said in a statement. "But it is not enough for the Council to express concern."
He said targeted sanctions would send a strong message.
already has designated Boko Haram a foreign terrorist organization, as has the European Union, making it illegal to contribute to the group. And Washington last year put a $7 million ransom on the head of Boko Haram leader Abubakar Shekau, who said in a video last week that he will sell the girls into slavery.
There also have been reports that some of the girls have been forced into marriage with their abductors, who paid a nominal bride price of $12, and that some have been carried across borders into Cameroon and Chad.
Lawan, the escape, said other girls who escaped later have told her that the abductors spoke of their plans to marry them.
She said the thought of going back to school terrifies her - either the burned out ruins of Chibok Government Girls Secondary School or any other school.
"I am really scared to go back there; but I have no option if I am asked to go because I need to finish my final year exams which were stopped half way through."