Police in Malawi have arrested 200 suspected members of vigilante mobs that have been killing people they believe are vampires. Nine people have been killed since mid-September in southern Malawi where there is a widespread belief in witchcraft.

The violence has prompted the UN and the U.S. embassy to declare some parts of the country no-go zones. The attacks spread last week to Blantyre, Malawi’s second largest city where a 22-year-old man was stoned then burned to death and another was stoned to death.

Both were accused of bloodsucking, although medical experts deny the existence of vampirism in Malawi. Amos Daka, head of the Medical Society of Malawi, said his group was not aware “that any one has adequate clinical evidence to support any of the many claims to date.” President Peter Mutharika has visited parts of the country affected by the violence.

On Oct. 10, the UN pulled staff out of two areas in southern Malawi. Newsmen report that Malawian President Peter Mutharika said the reports were “distressing and agonising”.

“This development has been of grave concern to the President and the entire Government,” his office said in a statement. A UN Department of Safety and Security report said the vampirism rumours appear to have originated in neighbouring Mozambique, although it was not clear what had sparked them.

It recommended the “temporary suspension of UN activities in the area until the situation is normalised