KADUNA, Nigeria (Reuters) – Nigerian criminals have killed two more student captives abducted from a northern university last week, said a state official on Monday, bringing the total number of executed hostages to five.

On Tuesday, armed men stormed Greenfield University in Kaduna state, killing one person and abducting an unknown number of students, the latest in a series of kidnappings at educational institutes that are mostly carried out for ransoms.

“Security agencies have just reported to the Kaduna State Government the recovery of two more dead bodies of Greenfield University students, killed by armed bandits today,” said Samuel Aruwan, Kaduna’s commissioner for its state ministry of internal security and home affairs.

A university spokesman did not immediately respond to calls and messages seeking comment.

Armed groups have repeatedly struck northern Nigerian schools and universities since December, abducting more than 700 students for ransom.

The government and security forces have largely been unable to stop the attacks as they struggle to contain worsening violence and criminality across the West African country.

(Reporting by Bosan Yakusak in Kaduna; Additional reporting by Garba Muhammad; Writing by Paul Carsten; editing by Grant McCool)