HARARE, April 17. /TASS/. An unknown terrorist group has attacked a minibus and taken 18 high school graduates hostage, Channels TV quoted the local authorities as saying.

The incident occurred on a highway in the southeastern state of Benue near the city of Otukpo, where the students were heading to take university exams. The criminals drove them in an unknown direction.

The security authorities launched an operation to search for the criminals and free the hostages.

Nigeria has been fighting terrorism for about 20 years, mainly in the north and northeast of the country. Now, it is rife in the southeast. Since December last year, the United States has been providing assistance in solving this problem, sending several hundred troops, weapons and ammunition. However, attacks by extremists, mainly from the Boko Haram group, are spreading to new areas.