Police say youths risking their lives climbing on to the roof of a west Belfast hospital are "disruptive and reckless".
CCTV footage has shown the young people trespassing on high buildings at the Royal Victoria Hospital (RVH) site.
A Belfast Trust spokesman said its concern was for "the comfort and wellbeing of our patients, some of whom are extremely unwell".
"It is also very dangerous for those involved," he added.
Sgt Anthony Greene of the PSNI (Police Service of Northern Ireland) said the young people's actions were "both disruptive and reckless, and could end up causing upset and injury".
He said those involved risked receiving a criminal record.
"I would also appeal to parents in the area to be aware of where their children are, and what they are up to. We all have a responsibility to work together and make this part of west Belfast a safer community in which to live," Sgt Greene said.
The trust spokesman added: "We are constantly reviewing our security measures to keep the environment safe, but we would appeal to them to think about the impact their activities have on our patients, as well as their own safety".