Yes, only the Police, but the Security Guards are well within their 'rights' to call the Police to issue tickets when necessary - it happened at a friend's building.
Only police can gave tickets. They can ask you not to do something and report you to the building management, but give you a ticket - NO only the police.
By powers I mean to issue tickets etc?! I was just wandering, as there is a very hyper Security Guard recently appointed in our car park and was curious to know if they really are able to exert any power?!