A 680-kilogram wrecking ball has broken loose from a crane cable in Pennsylvania, smashing into cars and injuring three people.
The incident occurred in Meadville, north of Pittsburgh in Pennsylvania, with the ball coming to rest in the boot of a car at an intersection.
The ball, about 90cm across, was being used on Monday to demolish part of a library at the town's Allegheny College when the cable snapped, police said.
The crane operator tried to stop it, but it rolled more than one kilometre downhill, damaging more than a dozen vehicles as it bounced from kerb to kerb, police said.
Most of the damaged vehicles were parked, but the ball slammed into the rear of a car stopped at an intersection, causing a chain reaction accident with two other cars at the traffic light, police said.
The ball finally lodged in the boot of a car, pushing the vehicle about six metres.
"I got out of my car and couldn't believe it when I walked back and saw this giant wrecking ball sitting in the trunk of the last car," said police Officer Brian Joseph.
Meadville is about 145 kilometres north of Pittsburgh.
© 2007 AP DIGITAL