The US has begun deploying manned aircraft over Nigeria to hunt for the hundreds of schoolgirls abducted by Boko Haram, officials have said, as authorities in the country scrambled to glean any useful information they could from a video posted by the militant group to YouTube.
The footage, including a 10-minute clip purporting to show some of the missing girls praying with their heads bowed, has been reproduced under orders from the state governor of Borno, where they were abducted four weeks ago.
Local officials were tasked with travelling to the remote area and circulating the video among families in a bid to verify the identity of the girls involved, and one mother has now confirmed that she spotted her daughter among those veiled and sitting on the ground.
Meanwhile, a spokesperson for the Obama administration in Washington said that the US had begun scouring the vast area of forest, described as being around three times the size of Wales, where Boko Haram were believed to be holding the girls.
“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 US official said.
State Department spokeswoman Jen Psaki told a news briefing late on Monday that the US was providing intelligence, surveillance and reconnaissance support. She said teams on the ground “are digging in on the search and coordinating closely with the Nigerian government as well as international partners and allies”.
In pictures: Nigeria kidnapped schoolgirls
In pictures: Nigeria kidnapped schoolgirls
A total of 276 girls were abducted from the northeastern town of Chibok, in Borno state, which has a sizeable Christian community. Some 223 are still missing
One of the kidnapped girls looks into a camera
One of the missing girls talking to the camera
The missing Nigerian schoolgirls, wearing the full-length hijab and praying in an undisclosed rural location. Boko Haram alleging they had converted them to Islam
Girls wearing the full-length hijab holding a flag reading "There is no god, but Allah" and "Mohammed is Allah's prophet"
A man claiming to be the leader of Nigerian Islamist extremist group Boko Haram Abubakar Shekau
Abubakar Shekau speaks on the video
Girls, wearing the full-length hijab and praying are filmed by an unidentified man (R) in an undisclosed rural location
People carry signs as they attend a protest demanding the release of abducted secondary school girls in the remote village of Chibok in Lagos
A protester demonstrates against the kidnapping of school girls in Nigeria, outside the Nigerian Embassy in London
Chief International Correspondent Christiane Amanpour and Prime Minister David Cameron appearing on the BBC1 current affairs programme
People participate in a "Bring Back Our Girls" campaign demonstration and candlelight vigil in Los Angeles
Girls holding heart shaped banners in a "Bring Back Our Girls" campaign demonstration and candlelight vigil in Los Angeles
14/19 South Africa
South Africans protest in solidarity against the abduction of hundreds of schoolgirls in Nigeria by the Muslim extremist group Boko Haram and what protesters said was the failure of the Nigerian government and international community to rescue them, during a march to the Nigerian Consulate in Johannesburg
Karilyn Coates (10) joins others in a candlelight vigil for the more than 300 girls abducted by Boko Haram in Nigeria, at All Souls Unitarian Church in Colorado Springs
Mothers of the missing Chibok school girls abducted by Boko Haram Islamists gather to receive informations from officials. Nigeria's president said that Boko Haram's mass abduction of more than 200 schoolgirls would mark a turning point in the battle against the Islamists, as world powers joined the search to rescue the hostages
Former Nigerian Education Minister and Vice-President of the World Bank's Africa division (3rd L) Obiageli Ezekwesilieze speaks as she leads a march of Nigeria women and mothers of the kidnapped girls of Chibok, calling for their freedom in Abuja
18/19 Bring Back Our Girls
Kelly Hoppen tweeted: 'Please make sure you do this, we must stand together and not forget them'
19/19 Bring Back Our Girls
E.L. Rock Star tweeted: 'Join The Movement'
At the weekend David Cameron joined the huge social media campaign #BringBackOurGirls, despite facing criticism from some observers on Twitter, and said that intelligence and counter-terror agents from the UK would be joining the larger US team already on the ground in Nigeria.
In the video released yesterday, around 130 girls appeared quiet, docile and passive against a rural backdrop. Officials from Nigeria, the US and Britain have reportedly been checking the footage against their own intelligence reports in an attempt to identify the location where it was filmed.
VIDEO: Boko Haram footage shows missing girls
In what was also the first sign that the girls’ captors may be willing to negotiate, a man claiming to be Boko Haram leader Abubakar Shekau suggested they could be traded for the dozens of Islamist militants held in Nigeria’s prisons.
The proposition was initially rejected out of hand by the government of President Goodluck Jonathan, which has been castigated at home for its seemingly lethargic response to the mass kidnapping and an earlier threat by Shekau to sell the girls as brides.
Read more: What is Boko Haram?
Abba Moro, the Nigerian Interior Minister, told Agence France Presse that the authorities were not prepared to trade the schoolchildren. Mr Moro said: “The issue in question is not about Boko Haram giving conditions.”
That position was backed by the father of one of the captive girls. He said: “It’s not right. They’ll do it again.”
But last night the government appeared to shift ground and leave open the option of negotiation by saying it was reviewing “all options”.
On Monday Israel became the latest country to have its offer of expert help accepted by Mr Jonathan.
The scale of the kidnapping and Boko Haram’s threat to sell the teenagers “in the market” have provoked international outrage and a global campaign to secure their release.