Gambo Isah, the spokesman for the police in Katsina, told Xinhua on the telephone that the armed attackers invaded the local farm on Sunday in Kampani Mailafia village in the state’s Faskari local government area, taking away the victims to an unknown location.

"They (the gunmen) took away a total of 21 farm workers between the ages of 15 and 19. Most of them were ladies, and only four among them were men," Isah said, noting the gunmen had already contacted some of the victims’ families for ransom.

The police spokesman said the farm manager had previously made a deal with the gunmen, who demanded "protection money" from farm owners to allow harvesting without disturbance.

Isah said the police, upon receiving a distress call from the village, had swung into action to rescue the victims and apprehend the fleeing gunmen.

Kidnapping for ransom is not uncommon in Nigeria, especially in the northern region where it has become an enterprise. Victims typically are released unharmed after ransom is paid.