The US is flying manned surveillance missions over Nigeria to try to find more than 200 schoolgirls kidnapped by the militant Islamist group Boko Haram.
Video: Foreign Affairs Correspondent Jonathan Miller reports from Abuja
Washington sent military, law-enforcement and development experts to Nigeria on Tuesday to help search for the missing girls who were kidnapped by Boko Haram militants from a secondary school in Chibok in remote north-eastern Nigeria on April 14.
It comes after militants released a video of about 130 girls on Monday, saying they could be swapped for jailed fighters.
“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,” a US official said.
State Department spokeswoman Jen Psaki told a news briefing on Monday that US teams on the ground were “digging in on the search and coordinating closely with the Nigerian government as well as international partners and allies.”
Two US officials, speaking on condition of anonymity, said the United States was also considering deploying unmanned, drone aircraft to aid the search.
One of the US officials told Reuters the United States had been carrying out the manned surveillance flights “for a few days” but did not elaborate.
Read more: Boko Haram - who are the group bringing terror to Nigeria?
Last week, US Undersecretary for Africa Linda Thomas-Greenfield told Reuters in an interview that Nigeria had requested surveillance and intelligence from the United States.
Nigerian President Goodluck Jonathan has said he believes the girls are still in Nigeria. The leader of Boko Haram has offered to release them in exchange for members of its group being detained, according to a video posted on YouTube on Monday.
Agence France-Presse reported that it had seen the video, which features a man claiming to be Abubakar Shekau – leader of Boko Haram. The 17-minute video shows around 100 girls praying in an undisclosed location. In the video, Boko Haram says the girls will be released in exchange for prisoners.
Mr Shekau said: “These girls, these girls you occupy yourselves with their affair – we have indeed liberated them. We have indeed liberated them. Do you know we have liberated them? These girls have become Muslims, they are Muslims.”
He goes on to call for the release of Boko Haram’s “bretheren”.
“It is now four years or five years that you arrested our bretheren and they are still in your prison. You are doing many things (to them). And now you are talking about these girls.
“We will never release them until after you release our bretheren.”