A manhunt is underway after a deadly shooting in northern Switzerland overnight into Sunday, police said, at what local media have reported was a rave event.

Aragau Cantonal Police said one person was killed and five others were wounded after shots were fired at the event in the town of Aarau, a scenic area known for its lush valleys, medieval castles and thermal springs.

The shooting happened at the Schachen horse racing track in the town, police said. A rave was being held at the venue at the time, according to public posts from the events organizers.

A large area around the venue has been cordoned off and police have asked members of the public to stay away from the area.

The shooter’s motive and the exact circumstances of the incident remain unclear, police said.