Seattle police say a man was injured when an explosive device attached to a parking pay station blew up as he walked by.

Police said on its website that it appears to be an "act of vandalism gone awry." Members of the police arson and bomb team processed the scene early Sunday after hospital staff who treated the man notified police.

The man told police that he was walking with a friend in the Ballard neighborhood of Seattle just after midnight Saturday when they heard an explosion. He said he was struck in the arm and was bleeding. Police say his injuries aren't life-threatening.

Police are investigating, and didn't provide other details. Police say was extensive property damage to electronic pay station.