DETECTIVES today revealed they are hunting a hallowe'en sex pest who exposed himself to a group of girls who were out playing trick or treat.

Police said the man struck as three 13-year-olds were heading home from Pasturegate Avenue, near Coal Clough Lane, Burnley.

The group said they spotted a "strange man" hiding in a dark alleyway at 8.30pm on Tuesday night.

The man emerged from the alleyway and indecently exposed himself to the children.

The terrified friends then ran to the nearest house and alerted a neighbour, who called the police immediately.

Detective Sergeant Derek Jones said: "The young girls were obviously very frightened and shaken after the man indecently exposed himself to them.

"We would urge people who were in the area, anybody who noticed anything suspicious or anybody may have seen the man before or after the incident, to contact us."

The flasher is described as a white male, about 30-years-old, 5ft 8ins tall, with short dark brown hair, and was wearing a black fleece, denim jeans and white lace-up trainers.

If anybody has any information about the incident they can contact Burnley police on 01282 425001 or alternatively call Crimestoppers in confidence on 0800 111 555.