German police have asked the public in an unusual move to help find a young man who was allegedly involved in the gang rape of at least two female high school students in the western town of Essen.

Police spokesman Lars Lindemann has described the crimes as "especially abhorrent and brutal."

Police said Wednesday that a group of five men aged 16-23 on two occasions lured the girls into their cars, took away their phones and then drove them to remote areas where they were raped.

They said three men have been arrested, that a 16-year-old is legally too young to be arrested and that the fifth is being sought, releasing his photo.

Their names were not released in line with German privacy laws.