Nigeria-based Boko Haram ’jihadists’ are behind horrendous violence in neighboring Cameroon, where they have kidnapped more than 1,000 children and used some youngsters as human shields, a top UN official said.

Nigeria-based Boko Haram 'jihadists' are behind horrendous violence in neighboring Cameroon, where they have kidnapped more than 1,000 children and used some youngsters as human shields, a top UN official said.

"The system they use is just inhuman," Najat Rochdi, UN humanitarian coordinator for Cameroon, told AFP in an interview in Geneva this week.

The north of the west African country borders the area in northeastern Nigeria where a violent Boko Haram insurrection has killed more than 15,000 people since 2009.

Starting last July, the jihadists began launching cross-border attacks, initially just hit-and-run strikes to grab food, Rochdi said.

But the attacks soon escalated with the militants burning villages and killing people, and, by the end of the year, kidnapping children.

"The information I have is around 1,500" have been taken since then, she said, adding that they were mainly used as servants, to help carry tents and fetch water.