Armed men attempted to kidnap more students in Nigeria’s Kaduna state overnight on Sunday, a state government official said, as 39 others from an earlier attack remain missing.

Attacks by armed gangs, usually referred to as bandits, have intensified across northwest Nigeria in recent years. Four school kidnappings since December have provoked nationwide outrage.

Some 39 students, including a pregnant woman, are still missing from Thursday’s abduction from the Federal College of Forestry Mechanization, in northwest Nigeria.

Samuel Aruwan, Kaduna state commissioner of internal security and home affairs, said police, army and others had repelled attacks on another school and at a local government office near Kaduna airport.

“The Kaduna state government extends its unequivocal solidarity to the military, police, Department of State Services and other security agencies, whose swift intervention prevented the bandits from abducting more persons,” Aruwan said.

All 307 students at the Government Science Secondary School in Ikara were accounted for, Aruwan said, adding that the army and air force also repelled an attack on senior staff quarters in Ifira village in Igabi local government area.

Aruwan did not refer to a video that circulated on Saturday of missing students from the Federal College of Forestry Mechanization, showing them being beaten and cowering.

In that video, a college student said their captors wanted a 500 million naira ($1.3 million) ransom.

“As a government, our focus is on getting back our missing students and preventing further episodes of school abductions,” Aruwan said.

President Muhammadu Buhari, speaking in a video message posted on Twitter on Sunday, ordered states to tackle security issues at every level and said military service chiefs would quickly address broader security issues.

“We are going to be very hard on the criminals,” he said, adding that “confidence must be restored in governance within the next six weeks.”

Reporting By Garba Muhammad in Kaduna; Writing by Libby George; Editing by Edmund Blair / REUTERS