Macedonian authorities say an device has exploded outside a police station in the capital Skopje, breaking windows and damaging cars but causing no injuries.

There has been no claim of responsibility for the pre-dawn attack Thursday, and no arrests have been made.

Police spokesperson Ivo Kotevski told The Associated Press that the unknown device, which was probably a hand grenade, exploded in the parking lot of the Aerodrom police station in eastern Skopje.

He said at least three parked cars were damaged.