The presidency thursday retracted its announcement that another Chibok girl was free, saying she was not one of the 219 whose kidnapping more than three years ago caused global outrage.
The presidency said on Wednesday evening that the teenager was picked up by the military after fleeing from Boko Haram jihadists.
But Laolu Akande, spokesman to the Vice-President Yemi Osinbajo, later tweeted that the girl was a junior secondary school â€œstudent from Chibok community.â€
In a text message to AFP thursday, he said the 15-year-old was â€œnot part of the 219.â€
Osinbajo is currently deputising for President Muhammadu Buhari, who is in London on medical leave.
In the Nigerian education system, junior secondary school is for pupils aged between 10 and 15. The 219 Chibok girls were in their final year of senior secondary school (SSS3).
The #BringBackOurGirls group, which has been campaigning for the release of the Chibok girls, also said the girlâ€™s name was not in their records.
â€œWeâ€™ve perused our list but canâ€™t find the name of the returnee said to be 1 of our #ChibokGirls,â€ it said on its Twitter account.
â€œWhether 1 of our missing #ChibokGirls or not, we are excited over everyone who regains their freedom & we look forward to all returning.â€
Boko Haram kidnapped 276 students from the Government Girls Secondary School in the remote town in Borno state on the evening of April 14, 2014.
Fifty-seven escaped in the hours that followed but 219 were not so lucky. Since then, 106 girls have been found, rescued or released, including 82 who were freed earlier this month in a prisoner swap deal for a number of Boko Haram suspects in custody.
In May 2016, just hours after the first Chibok girl was found, the military said a second had been rescued. The girl later turned out to be a younger student at the same school, who was also kidnapped but not part of the 219.
Boko Haram has kidnapped thousands of young women and girls during its eight-year insurgency to establish a hardline Islamic state in northeast Nigeria.
Young men and boys have also been forcibly recruited to fight in the jihadistsâ€™ ranks