Officials in a Siberian region on Wednesday banned Halloween parties from school classrooms, warning that they foster extremism and encourage children to dabble in a "cult of death".

The education ministry of the Omsk region in Siberia sent out a letter telling schools that "holidays that are propaganda for extremist moods will not be celebrated," its website said Wednesday.

Halloween, a pagan holiday celebrated widely worldwide on October 31, has become increasingly popular with young Russians who hold fancy-dress parties and go to themed club nights.

The Omsk education authority said it reacted after a warning from the regional Parents' Assembly, a conservative lobby group.

Celebrating Halloween has "negative consequences" because of its "mystical content and propaganda of the cult of death," the regional ministry said.

The Russian Orthodox Church's head of public affairs, Vsevolod Chaplin, has also warned against getting drawn into the occult through Hallowe'en customs.

"People only think it's a laugh - harmless and fun. The evil spirits think otherwise," he told the RIA Novosti news agency.