Gunmen in northwest Nigeria have abducted more than 300 girls from a school in one night. Police believe they are holding some of them in a forest.

This is the second incident of its kind in a little over a week. Militants and criminal gangs are becoming increasingly prevalent in the region. No specific group has claimed they are responsible for the attack.

Police in Zamfara have started a search-and-rescue operation with the army to find the “armed bandits” who took the 317 girls from the Government Girls Science Secondary School in the town of Jangebe.

“There’s information that they were moved to a neighboring forest, and we are tracing and exercising caution and care,” Zamfara police commissioner Abutu Yaro said.

According to Zamfara’s information commissioner, Sulaiman Tanau Anka, the gunmen stormed in the building and began firing sporadically during the 1 a.m. raid.

“Information available to me said they came with vehicles and moved the students, they also moved some on foot,” he said.

Jihadist groups Boko Haram and Islamic State West Africa Province first carried school kidnappings, but many other militant groups have adopted the same tactic.

The popularity of such abductions could be fueled by the government payoffs that militant groups receive in exchange for child hostages.

“The situation at Jangebe community is tense as people mobilized to block security operatives, journalists and government officials from getting access to the main town,” one man said.

Parents also have little faith in the government returning their kidnapped daughters, said Mohammed Usman Jangebe, the father of one abductee.

“We are going to rescue our children, since the government isn’t ready to give them protection,” he said.

“All of us that have had our children abducted have agreed to follow them into the forest. We will not listen to anyone now until we rescue our children,” Jangebe said.