MAIDUGURI, Nigeria (AFP) - The Nigerian military admitted on Friday that most of the 129 girls kidnapped by Boko Haram Islamists in a shocking school raid in the volatile northeast remained missing, amid fears the girls might be used as human shields or sex slaves.
The military had claimed on Wednesday that all but eight of the girls snatched from their school in the state of Borno managed to escape the gunmen's clutches, contrary to comments by the state government and the school principal.
"The defence headquarters wishes to defer to the school principal and governor's statement on the number of students still missing," defence spokesman Chris Olukolade said in a statement on Friday.
He said vigilante groups and hunters were assisting the authorities in the frantic search for the girls, who were grabbed from the Government Girls Secondary School in the Chibok area of Borno late Monday.
Borno state education commissioner said that 30 girls had now escaped from the Islamists. "At the moment we have taken custody of 30 girls," Mallam Inuwa Kubo said in a statement.
"This means about 99 girls are still missing because the principal of the school, Asabe Kwambura, confirmed that 129 girls were in the school when the gunmen arrived", on late Monday, he said.
"The aim is for us to take proper account of our 129 students who were at the hostel on the day of that unfortunate attack," he said.
"By our records, of 129 students at the hostel at the time of that unfortunate incident, we are expecting the return of about 99 students."
The mass abduction sparked global outrage and came just hours after the deadliest attack to hit the capital Abuja, where a bomb blast also blamed on Boko Haram killed at least 75 people.
Boko Haram's extremist uprising, aimed at creating a strict Islamic state in northern Nigeria, has killed thousands of people since 2009.
Parents of the missing girls swarmed the home of Chibok's tribal chief on Thursday, demanding answers after the military claimed the girls were free, residents said.
Others decided to scour the remote area in a desperate search for girls who may have escaped. "Some of our parents are even combing the bush," Mr Kwambura said, adding that families had pooled money to buy fuel for motorcycles and other vehicles to help with the search.
Boko Haram's name loosely translates as "Western education is forbidden" and the group has repeatedly attacked schools and universities.
Students have been massacred in their dormitories and bombs set off at university campuses, but the mass abduction specifically targeting girls is unprecedented.
A top security officer said the girls might have been abducted by the Islamists to serve as human shields, domestic helpers and sex slaves.
"The terrorists are desperate for survival. The military offensive is taking a heavy toll on their rank and file," the officer, who did not want to be named, told AFP.
"The female hostages are being used as shield during battles with the military. Some serve as cooks and many more as sex slaves," he said.
A state government official said girls who had escaped captivity in other kidnapping cases had confirmed these fears.
"The insurgents are using women to cook for them and do other house chores," he said, adding that the captors also "use some of the captives as sex machines".
Another source said there were also concerns that the fleeing Boko Haram Islamists might have buried landmines and explosives in their hideouts to hinder the ongoing security operation to free the girls.
Borno's governor Kashim Shettima has offered a reward to anyone with information leading to the return of the schoolgirls.
President Goodluck Jonathan met his security chiefs on Thursday to review the latest unrest and another security meeting has been set for next week.
The Boko Haram insurgency has cost more than 1,500 lives already this year, the deadliest stretch in the five-year uprising.
The police said on Friday it had stepped up security nationwide to ensure a violent-free Easter festivities.
"The operations encompass extensive counter-terrorism sweeps, detailed overt and covert surveillance operations, intelligence-driven raids, arms mop-up exercise, special stop and search exercise, amongst others," the force said in a statement