Philadelphia police said someone set several police cars on fire early Monday morning in Philadelphia.
The police cars were empty; no one was hurt and the small fires were quickly extinguished. However, the fires damaged at least four police cruisers, police said.
In one case, it appeared a device was put in the wheel well of a car. In another, a flammable liquid appeared to have been poured on the car.
The fires happened at several locations in West Philadelphia, including 40th and Chestnut streets and 39th and Lancaster, as well as in Center City at 10th and Vine and 7th and Chestnut.
There is no description of the suspect, but the locations are heavily traveled streets with many businesses that may have surveillance cameras.
Police are being urged to keep their cruisers in sight.
Police did not discuss a possible motive for the fires.