Belfast children - some as young as 12 - were discovered partying in a field in the south of the city by police.
Both the PSNI and the fire service were alerted to the incident in Lagan Meadows around 9pm on Saturday evening as up to 100 youngsters aged between 12 - 16 were discovered drinking and dancing.
Some of the young revellers were discovered 'the worse for wear with drink', the police said.
And the fire service had to put out some gorse fires that had broken out.
The PSNI in south Belfast reminded parents to be aware of where their children at all times following the incident.
In a Facebook post, Constable McCoy cautioned: "This area is very dark, has barbed wire fences, and is beside the river.
"Listen I don't want to be a killjoy, but equally I don't fancy pulling someone out of the river, and I am sure you agree fire service have more important calls to attend."