Youths are being hunted after they smashed a window of a bus travelling along a Sheffield street.
The bus was travelling along Beaver Hill Road, Woodhouse, when it was targeted over the weekend.
Youths were seen running away from the scene afterwards.
South Yorkshire Police said the damaged window will cost £500 to repair.
A South Yorkshire Police spokesman said: "It is becoming a worrying trend with the buses being attacked on Beaver Hill Road, Woodhouse.
"In some parts of the city where similar incidents have occurred, bus companies have stopped running services after certain times.
"This can then affect everyone.
"If anyone has any information on who maybe responsible please ring. Your information will be treated in the strictest confidence."
Call South Yorkshire Police on 101.