Children are causing chaos at an upmarket leisure centre in Middleton by breaking into the outdoor pool and stealing gym equipment and food.
Police said the situation at David Lloyd on Heywood Old Road is 'getting out of hand'.
Staff are constantly having to make repairs, they said.
"Now none of us here at the police station are ever going to say we've not done things we shouldn't as kids, but this is now getting out of hand.
"Parents reading this may or may not be aware that some of these kids could be theirs.
"Jumping in the pool when the gym is closed is one thing, but now this group have turned themselves into burglars - breaking into the gym itself to steal food and drink, in addition to gym equipment.
"The gym is constantly having to make repairs to the pool and lifeguard stations, putting other peoples safety at risk", a post on the GMP Middleton Facebook page said on Friday.
The post urged parents to have a word with their children if they suspected they may be involved.
"We have managed to identify from CCTV some of these youths and will be taking appropriate action, but also as parents, if you think your child may be part of this group, please instill into them that a huge fence is around the gym and is a very big give away that you shouldn't be going in.
"It may be a laugh to jump in a pool when you shouldn't but god forbid, the worse happens and someone drowns.
"It will be asked, what did the police do, what did the gym do .....What did the parents do......Please have a word over the weekend to instil the risks."
