The fate of 115 female students abducted by Islamic extremists was thrown into uncertainty when their school principal denied the Nigerian military's report that almost all the pupils had been freed.

"Up till now we are still waiting and praying for the safe return of the students ... the security people, especially the vigilantes and the well-meaning volunteers of Gwoza are still out searching for them," said the principal, Asabe Kwambura.

She said only 14 of the 129 girls and young women kidnapped by gunmen before dawn on Tuesday have returned to Chibok town - four who jumped from the back of a truck and 10 who escaped into the bush when their abductors asked them to cook a meal.

The principal directly contradicted Major General Chris Olukolade, the Defence Ministry spokesman, who said in a statement on Wednesday that Ms Kwambura herself had confirmed all but eight of the students have been accounted for.

Ms Kwambura was adamant: "So let it be clear that all the information passed on to the media by the military concerning 107 girls is not true."