MAIDUGURI: Heavily armed Boko Haram militants abducted more than 100 girls from a secondary school in northeast Nigeria, sparking a search by soldiers to track down the attackers, a security source and witnesses said Tuesday.

Some of the schoolgirls in the Chibok area of southern Borno state narrowly escaped their kidnappers by jumping off a truck in the middle of the night as the gunmen sought to cart them away, according to multiple witnesses.

A security source who requested anonymity said the attackers were members of Boko Haram, a radical group whose name means “Western education is forbidden.”

The group has repeatedly attacked schools in the northeast during an insurgency that has killed thousands since 2009.

Asked to confirm media reports that 200 girls had been taken from the Government Girls Secondary School in Chibok, the source said: “The number is not up to 200, but it is over 100.”

The gunmen, riding in trucks and on motorcycles, stormed the town after sundown, torching several buildings before opening fire on troops who were guarding the school, said Chibok resident Salisu Ibrahim in an account supported by other witnesses.

The gun battle, which occurred on Monday, reportedly lasted several hours but the Islamists ultimately overpowered the troops and entered the school, said Emmanuel Sam, an education officer based in Chibok.

Sam, who fled to Borno's capital Maiduguri after the attack, said “many” girls had been abducted, but declined to offer a more precise figure. He said the girls had been scheduled to sit exams this week.

The Islamists loaded the girls onto trucks and drove away, multiple witnesses said.

“We were able to follow the path of the truck and we found it broke down deep in the bush,” the security source told AFP.

“We are now trying to locate the whereabouts of the abducted girls,” he added.

Borno, Boko Haram's stronghold and where the group was founded more than a decade ago, is a remote region with notoriously bad roads.

Ibrahim, also speaking from Maiduguri, told AFP that “some of the girls jumped out of the truck,” as it moved and some of those who escaped managed to make it back to Chibok.

In an attack earlier this year in Borno state, witnesses said Boko Haram gunmen surrounded a girls' school, forced the students to leave and ordered them to immediately return to their villages.

The Islamists have been blamed for a series of school massacres, including the mass shooting of students in their sleep earlier this year in Yobe state.

Boko Haram's insurgency has crippled education in Borno, with schools across the state having been shut down.

But a mass abduction specifically targeting girls is unprecedented in the group's uprising.