Police are hunting a group of youngsters after a pellet was fired at a bus on the outskirts of Dumfries.
The driver was forced to stop after a passenger window shattered at about 18:15 on Saturday.
Police said the damage to the bus window was consistent with a pellet from an air weapon, BB gun or catapult.
Nobody was injured in the incident on the A76 near the Newton Gardens filling station.
The driver pulled over after being alerted by passengers, who reported seeing a group of children running away from the scene.
A Dumfries and Galloway Constabulary spokesman said they wanted to hear from anyone who could help identify those responsible.