The latest abduction took place late Thursday night at the Federal College of Forestry Mechanization, Afaka, in the Igabi local government area of Kaduna state, police said.

“About 30 students, a mix of males and females, are yet to be accounted for,” Samuel Aruwan, Commissioner for Kaduna State Ministry of Internal Security and Home Affairs, said in a statement. Several staff of the school were also kidnapped, he added.

Also read: Nigerian governor says 279 kidnapped schoolgirls are freed

Aruwan said the attack was carried out by a large group of “armed bandits,” adding that the military engaged the attackers and were able to take 180 staff and students to safety.

An unspecified number of the students were injured and are receiving medical attention at a military facility. Security forces “are conducting an operation to track the missing students,” Aruwan said.

Also read: Hundreds of Nigerian schoolgirls taken in mass abduction

Nigerian authorities also said that “bandits” were behind the earlier abduction of 279 schoolgirls late last month in the northwest, referring to the groups of armed men who kidnap for money or to press for the release of jailed members of their groups. Those girls were later freed following negotiations with the government, and it is not known whether a ransom was paid.

The Islamic extremist group Boko Haram is also known to kidnap young women and force them into marriage, most notably the 2014 attack on the Chibok secondary school in Borno state. That mass abduction sparked international outcry and prompted the #BringBackOurGirls campaign. Of the 276 girls taken, more than 100 are still missing nearly seven years later.