Youngsters are being told to stay away from a quarry after being spotted swimming on the site.
Police issued the warning after reports were made to suggest children had been seen trespassing and playing in the water at Darrington Quarry.
A police spokesman said: “It is important to remember that the quarry is not a playground and is a very dangerous place to go which has unsupervised open waters and unsafe terrain and rocky areas.
“That is why it is fenced off and privately owned with security guards and dogs on the site.
“Our officers will be conducting checks within the area and positive action will be taken against anyone found to be on the enclosed premises.”
Police send out a warning each summer about the dangers of swimming in rivers and unsupervised stretches of water during the hot weather.
There have been a number of drowning deaths in district over the years.