US experts have been poring over video footage to try to trace more than 200 schoolgirls that were abducted. Nigeria has rejected an offer by the Islamist group Boko Haram to return the girls in a prisoner exchange.
US officials said on Monday that their experts were closely examining a video released by Boko Haram for any clues about the whereabouts of more than 200 girls who were abducted.
"We are providing intelligence, surveillance and reconnaissance support," said State Department spokeswoman Jen Psaki. "Our intelligence experts are combing through every detail of the video for clues that might help ongoing efforts to secure the release of the girls," said Psaki. "We have no reason to question its authenticity."
The video was purported to show some 130 of the girls wearing gray Islamic veils and chanting verses from the Koran, with treetops in the background. It is thought the footage may provide vital clues that could help with the search.
Another senior White House official, who did not wish to be named, said the assistance being provided now involved surveillance using manned US aircraft.
"We have shared commercial satellite imagery with the Nigerians and are flying manned ISR (intelligence, surveillance and reconnaissance) assets over Nigeria, with the government's permission," the official told reporters. However, an official statement, including details of the aircraft and where they had come from, was not immediately available.
A 30-strong team from the US arrived last week in Nigeria, to help in the search for the girls who are aged between 16 and 18. Almost 200 girls were snatched from their boarding school in the northeast of the country on April 14. The act sparked public outrage, including a prominent Twitter campaign, with France subsequently offering to host a summit to discuss the Boko Haram threat.
Britain and France have also deployed experts to Nigeria, with London saying its aim, as well as finding the girls, was to assist in the defeat of the Boko Haram network as a whole. China, Israel and Spain have all offered help of their own.
The Nigerian government on Monday said it would not agree to a deal proposed by Boko Haram's leader Abubakar Shekau in the video, offering the girls' safe return only in exchange for captured fighters.
Boko Haram's violent campaign to impose a strict brand of Shariah law on Nigeria has killed more than 1,500 people this year alone. Thousands more have died since the group's campaign of violence erupted in 2009.
rc/crh (AFP, dpa, Reuters)