MAIDUGURI/ABUJA - Nigeria's military said on Wednesday its forces had freed most of the more than 100 teenage schoolgirls abducted by Islamist Boko Haram militants and were continuing the search for eight students still missing.

In a brief statement sent to media, spokesman Major General Chris Olukolade said one of the "terrorists" involved in Monday's abduction of female students from the Chibok government secondary school in northeast Borno state had been captured.

"With this development, the Principal of the school has confirmed that only eight of the students are still missing," Olukolade said, adding that the rescue operation was continuing.

He did not specify exactly how many of the girls snatched from their school by the anti-government Islamist movement had been rescued or give details of how or where they were freed.

An earlier statement from the military had put the total number of students kidnapped at Chibok at 129, and said pursuing troops were "closing in" on the abductors' hideout.

A spokesman for Nigerian President Goodluck Jonathan, Reuben Aabati, told Reuters he had been informed some of the kidnapped girls had been freed but could not specify how many.

The mass abduction of schoolgirls aged between 15 and 18 has shocked Nigeria and showed how the five-year-old Boko Haram insurgency has brought lawlessness to swathes of the arid, poor northeast, killing hundreds of people in recent months.

It occurred the same day a bomb blast, also blamed on Boko Haram, killed 75 people on the edge of the capital Abuja, stirring fears of violence spreading from the north of Africa's No. 1 oil producer and most populous nation.

Abati said Jonathan, who had ordered the military to secure the release of all the missing girls, had called a meeting of his National Security Council for Thursday to review the security situation in the country.

With elections due in February, Jonathan is under intense pressure to contain the Boko Haram insurgency and additional communal sectarian violence in Nigeria's centre-north which badly tarnish the West African state's newly acquired status as the largest economy on the continent.

Earlier, officials said the Boko Haram raiders had duped the schoolgirls into thinking they were soldiers come to protect them before abducting them. A few of the girls later escaped.

"When we saw these gunmen, we thought they were soldiers, they told all of us to come and walk to the gates, we followed their instructions," 18-year-old Godiya Isaiah, who managed to flee from her abductors, told Reuters.