The Ninewells Hospital helipad often used to ferry critically ill patients for emergency treatment has been attacked by vandals.
Police say beacons surrounding the helipad were damaged at around 9pm on Monday.
The helipad is on the grass area at Maggie’s Centre near the entrance to the accident and emergency department.
The concrete landing square is surrounded by a ring of recessed landing beacons and a number of these were damaged and the bulbs smashed.
Officers are keen to trace three youths seen in the area at time.
One is described as a 12-14-year-old boy, of heavy build who was wearing Bermuda shorts. The second is 12-14-year-old boy, and the other is a girl aged about eight.
Anyone with any information is asked to contact Tayside Police on 0300 111 2222 or speak to any officer.