Extra police officers are to be deployed onto the streets of Belfast this weekend to stop teenagers taking part in organised fights.
Crowds of up to 80 schoolchildren, some as young as 12, have been using Facebook to organise pre-arranged fights to settle feuds.
Weapons, including knives and hammers, have been recovered by police at the scene of some of these arranged incidents over the last two weekends.
North Belfast neighbourhood police officer Sgt Brian Caskey said that although a "small number" of teens are behind the organisation of the fights, they are becoming "the only show in town".
He said that the fights are possibly being organised to settle fall-outs over a breakdown in a relationship or a perception over something that may have happened in school. Over the last few weekends up to 80 schoolchildren gathered in the Brougham Street and Waterworks areas to watch pre-arranged clashes.
Police and community workers arrived at the scenes just in time to disperse the crowds before anyone was seriously injured. It is believed that another fight has been arranged for tomorrow.
"This is very dangerous behaviour. It will not be tolerated. We would appeal to parents to engage with their children, find out where they are heading and check the social networking sites," Sgt Caskey added.
Gerry O'Reilly, from the Community Bridges Project in the Duncairn Gardens area said the fights have become "a weekend activity to look forward to" for some young people. He added that half of the large crowd that gathered to watch a fight at the weekend were young girls, "dressed up for a night out socialising".
"We have contacted schools and youth centres to explain what was happening and hopefully they too can use their influence to stop this from happening."
Harry Smith, a community worker in the Tiger's Bay area, said it was time legislation was introduced to enable police to act on information being produced on social networking sites.
"Unless we can stop this there will be serious injury or death.
"We need some sort of mechanism to monitor the impact social media is having on our local communities. Currently young people can freely arrange these events on the social networking sites without any accountability at all," Mr Smith added.