(Corrects to reflect that escaped girl is not a "Chibok girl")
ABUJA, May 18 (Reuters) - A Nigerian schoolgirl has escaped from her captivity by Islamist insurgency Boko Haram, the government's official Twitter account said on Thursday.
A presidential spokesman mistakenly identified the girl on Wednesday as one of a group of roughly 270 girls abducted by Boko Haram in April 2014. Thursday's tweet made clear she was also taken in that year from Chibok but on a different occasion.
Vice President Yemi Osinbajo told a cabinet meeting in the capital Abuja on Wednesday that the schoolgirl "had been found after she escaped from her captors", the presidential spokesman said.
"I learnt she is already being brought to Abuja," he said, giving no further details.
Of the 270 girls originally kidnapped, around 60 have escaped and more than 100 have been released. About 100 more are still believed to be in captivity.
Boko Haram's insurgency has killed more than 20,000 people and displaced more than two million since 2009 in an attempt to create an Islamic caliphate in northeastern Nigeria.
Three years ago, the abduction of the girls from their secondary school by Boko Haram sparked global outrage and a celebrity-backed campaign #bringbackourgirls.
For more than two years there was no sign of the girls. But the discovery of one of them with a baby last May raised hopes for their safety, with a further two girls found in later months and a group of 21 released by the Islamist militants in October.
Although the Chibok girls are the most high-profile case, Boko Haram has kidnapped thousands of adults and children, many of whose cases are neglected, say aid organisations.
The group often uses those captives, especially young girls and women, as suicide bombers.
(Reporting by Felix Onuah; Writing by Paul Carol; Editing by Gareth Jones)