MAIDUGURI, Nigeria (AP) — Gunmen abducted at least 20 students in northwestern Nigeria during an attack early Friday that targeted their school, local media and authorities reported Friday, the latest in a cycle of violence in the country’s troubled northern region.

The students were taken hostage when the gunmen broke into their accommodation near the Federal University Gusau in Zamfara state’s Bungudu district, Zamfara police spokesman Yazid Abubakar said.

Abubakar couldn’t confirm the exact number of abducted students, though local media reported the figure as 24, quoting other students who also said that the kidnap victims were mostly female students.

Abductions of students from schools in northern Nigeria are common and have become a source of concern since 2014 when Islamic extremists kidnapped over 200 schoolgirls in Borno state. The frequency of the attacks though has reduced over the last year and Friday’s incident presents a new challenge to Nigerian President Bola Tinubu who only took office in May.

The assailants in the latest incident arrived in large numbers after earlier confronting the security personnel in the area, residents said, highlighting once again the inadequate security presence in remote communities across Nigeria.

“The security forces, previously alerted to the situation, engaged the terrorists who subsequently retreated into the bush. (But) the terrorists later returned to the community to carry out the abductions,” said Abdullahi Ilela, a resident of the community.

No group has claimed responsibility for the latest attack though the blame quickly fell on the bandit groups that have been targeting remote communities across Nigeria’s northwest and central regions. Authorities say the groups are mostly made up of young pastoralists from Nigeria’s Fulani tribe caught up in a decades-long conflict between host communities and herdsmen over limited access to water and land.

Abubakar, the police spokesman, said a manhunt has been launched to arrest the attackers.

“A combined search and rescue team made up of the police, the army and the air force have embarked on the search and rescue,” he said.