Abuja (AFP) - Nigeria has claimed the rescue of a second Chibok girl but a campaign group on Friday said she was captured separately from the 219 held by Boko Haram, as questions were raised about the first release.
Serah Luka was among 97 women and children rescued in the Damboa area of Borno state in northeast Nigeria on Thursday morning during military operations against the Islamist insurgents.
The BringBackOurGirls group said background checks had established she was a student at the same school but was in a different class to those seized on April 14, 2014.
"She was an SSS1 learner at (Government Girls Secondary School) Chibok, who was abducted by the insurgents in her home in Madagali (in neighbouring Adamawa state)," said spokesman Sesugh Akume.
SSS1 is the first of the final three years at secondary school in Nigeria. The 219 schoolgirls were in SSS3.
The announcement about Serah's rescue came just hours after the first girl to be found, Amina Ali, met President Muhammadu Buhari in the capital, Abuja.
Buhari, who was criticised by human rights campaigners for making "political capital" so soon after she was found, said her return gave a "unique opportunity" to find the remaining hostages.
The 19-year-old was discovered with her four-month-old baby girl, Safiya, and a man she described as her husband near Boko Haram's Sambisa Forest enclave on Tuesday.
Nigerian troops have pushed out Boko Haram from captured territory in the last 15 months and have been conducting operations in the former game reserve in Borno state since late April.
The mass kidnapping of the 219 Chibok schoolgirls provoked global outrage and brought unprecedented attention on the Boko Haram conflict, which has killed at least 20,000 since 2009.
- Not on the list -
The head of the Abducted Chibok Girls Parents group, Yakubu Nkeki, said that unlike the first announcement about Amina, the military had not contacted them beforehand to establish Serah's identity.
Only two girls with the surname Luka were on the list of abducted girls and none was from Madagali, which has been repeatedly attacked by the rebels, he added.
The military said the teenager was believed to be a Christian pastor's daughter but Nkeki said there were only four priests on the list of parents and none was called Luka.
"I can say in my capacity as the head of the Chibok Abducted Girls Parents group that this girl is not among the abducted Chibok girls," he told AFP.
In response, a senior military source stood by the army's statement, saying it was "beyond reasonable doubt" that she was among the girls snatched.
The BringBackOurGirls group, which has campaigned for the release of all hostages, said: "Every citizen returned is victory for us all."
Thousands of women and girls have been kidnapped in the conflict. Former hostages have said they were forced to marry Boko Haram fighters, cook, clean and become sex slaves.
- Sign of talks? -
This week's developments have raised hopes that the remaining students will be released and follows a so-called "proof of life" video sent to the government earlier this year.
Until then, none of the kidnapped schoolgirls had been seen since May 2014, when they were shown in a Boko Haram video, apparently converted to Islam and reciting passages from the Koran.
Nigeria's government was cautious about the "proof of life" video because of difficulties establishing whether those who sent it had the authority of the group's leadership to request talks.
Security analysts tracking the conflict suggested Amina may have been released as a gesture of "good faith" by Boko Haram elements rather than by simply military action.
Ryan Cummings, from Signal Risk, said escape was unlikely given that the Chibok girls were said to have been heavily guarded at militant camps in the Sambisa Forest, a vast semi-desert scrubland.
"It seems very fortuitous that the hostage (Amina), child and BH husband just happened to run into a CJTF (civilian joint taskforce) patrol as described", he told AFP in an email.
Nigeria's military have described the man found with Amina as a "suspected Boko Haram terrorist".
Cummings also suggested reports of his "defection" with such a prized asset, straight into the hands of the Nigerian army and military intelligence, also seemed unlikely.