Maiduguri - Authorities on Wednesday revised downward by four the number of schoolgirls held captive by Boko Haram, denying media reports that the hostages had escaped from the militants in recent days.
A source at the government in north-eastern Borno state who requested anonymity said the number of girls who are currently missing was now 219, not 223 as previously reported by most media.
Police in Borno said 276 girls were kidnapped by the militants on 14 April from a secondary school in the town of Chibok.
Authorities had said that 53 of the hostages had escaped in the first days following the attack.
But, following closer investigation, it emerged that in fact 57 had run to freedom shortly after the attack but that the parents of four girls had neglected to inform officials that their children had safely returned, according to the source.
Borno's education commissioner, the point man on the hostage crisis, revealed the revised figures to members of a presidential committee when the panel visited the state capital Maiduguri last week, the source added.
The commissioner "was furious with the parents for keeping the government in the dark", about the fact their children were among those who had escaped, the source added.
Some local media on Wednesday reported that the girls had escaped in recent days or had perhaps been released by the militants after falling ill.
Calculating the number of girls taken in the attack has been hampered from the outset by conflicting reports from parents, officials and the security forces.
Days after the attack, the military said all but eight girls had been freed, a claim that was swiftly retracted.
Some parents in Chibok have insisted that more than 300 girls were taken, but in recent weeks most media have reported the figures provided by police in Borno, which have the backing of the state government.