Children as young as 12 have been arrested for taking part in sectarian fights arranged on Facebook.
There has been a surge of pre-arranged fights among youths at interfaces in south and east Belfast in recent weeks.
In the past month alone 21 young people have been arrested, police said.
Yesterday the PSNI warned those taking part they were jeopardising their futures.
Chief Inspector Robert Murdie, PSNI area commander for South Belfast, said: "Police are working with Belfast City Council and there will be an increased presence of police and park wardens in the area. Police are also working with local community groups to highlight the impact that a criminal record can have on an individual."
Over the weekend rival factions gathered in Ormeau Park and three young people aged 12, 14 and 16 were arrested in the park in connection with the altercations. It is believed that social media networks such as Facebook and Twitter were used to arrange the confrontations.