About 190 schoolgirls remain missing after being abducted last week by Boko Haram insurgents, their head teacher, Asabe Kwabura, told the British Broadcasting Corporation on Monday.
She said the parents of 230 girls had reported them missing but that 40 had managed to escape from the insurgents.
The 190 figure is far more than the 77 given earlier by government officials.
The Associated Press had reported that parents of the pupils of Government Secondary School, Chibok told Borno State Governor Kashim Shettima when he visited on Monday, that 234 girls were abducted.
When news first emerged of the kidnap last Tuesday, initial reports said more than 200 students were abducted, but state officials said the correct figure was about 130.