Boko Haram
Boko Haram is suspected in a bombing at a soccer field that killed a number of people. REUTERS/Stringer

Suspected Islamist gunmen attacked a college in northeastern Nigeria in the middle of the night and killed up to 50 students, sources told the Associated Press.

Northeastern Nigeria is under a state of emergency amid an Islamist insurgency by the Boko Haram group, which is fighting to overthrow Nigeria's government to create an Islamic state, and has launched a number of attacks on schools.

The assault began around 1 a.m. local time on Sunday. “They attacked our students while they were sleeping, they opened fire at them," Molima Idi Mato, provost of the Yobe State College of Agriculture in Gujba, told the Associated Press. He said he could not give an exact death toll as security forces still are recovering bodies of students, mostly between 18 and 22 years of age.

A surviving student, Ibrahim Mohammed, told the AP that the extremists rode into the college in two double-cabin pickup all-terrain vehicles and on motorcycles, some dressed in Nigerian military camouflage uniforms. The student added that the gunmen appeared to know the layout of the college, attacking the four male hostels but avoiding the one hostel reserved for women. "We ran into the bush; nobody is left in the school now," Mohammed said.

Almost all those killed were Muslims, as is the college's student body leader, Adamu Usman, a survivor from Gujba who was helping the wounded at the hospital, told the AP.

The Nigerian military had collected 42 bodies and transported 18 injured students to Damaturu specialist hospital, according to a military intelligence official. The school's other 1,000 students fled the college.

Most schools in the area closed after militants on July 6 killed 29 pupils and a teacher, burning some alive in their hostels, at Mamudo, outside Damaturu. Boko Haram militants have killed more than 1,700 people since 2010 in their quest to install an Islamic state. The Islamic militant group's name translates from the local Hausa language as "Western education is a sin." The group often targets schools and churches. In 2011 and 2012, Christmas attacks were blamed on them.

Several hundred people have died in assaults over the past few weeks.

Boko Haram leader Abubakar Shekau last week published a video to prove he is alive and was not killed during the crackdown by the military.

Boko Haram's insurgency is also putting pressure on the economy of Africa's most populous nation. Nigeria's security spending has risen to more than 1 trillion naira ($6.26 billion) per year, or around 20 percent of the federal budget, according to Reuters.