Gunmen kidnapped scores of schoolgirls in northeastern Nigeria late Monday, in a mass abduction thought to be carried out by members of Boko Haram, the same armed network that killed 75 in a bus bombing in the country’s capital a day earlier.

"Over 100 female students in our government secondary school at Chibok have been abducted," Audu Musa, who teaches in another public school in the area, said, adding that the people responsible were believed to be members of Boko Haram. The armed group, who has as its aim the establishment of an Islamic state in northern Nigeria, has previously attacked schools in the region.

The kidnappings, which were first reported by the BBC on Tuesday, took place after midnight in Chibok in the Borno state, a stronghold for Boko Haram.

Gunmen killed a soldier and police officer guarding the school, then took off with at least 100 students, a State Security Service official said. Some of the teens managed to escape from the back of an open truck, officials said.

A local government official said he did not know how many of the girls have escaped but that "many" have walked through the bushes and back to Chibok. The girls were piled into the back of an open truck and, as it was traveling, some grabbed at low-hanging branches to swing off while others jumped off the slow-moving vehicle, he said. The two officials spoke on condition of anonymity because they are not authorized to give information to reporters.

Boko Haram is held responsible for the deaths of thousands of Nigerians in violence that has plagued the country in recent years. Though their early attacks targeted security services, politicians and other high-profile individuals, the assaults have quickly spread to United Nations buildings, churches, schools and civilians, according to a report released this month by the International Crisis Group, a nonprofit organization dedicated to preventing and resolving conflict.