A potential fight involving up to 80 schoolchildren, some as young as 11, was averted by police in Devon.
Police said the force could apply for dispersal orders
Officers were called to Cullompton on Saturday afternoon after reports a fight had been arranged by children from schools in mid-Devon.
Police said the brawl was orchestrated via the internet by groups from Tiverton, Cullompton and Uffculme.
Children were said to be carrying metal bars, wood, baseball bats and bicycle chains to use as weapons.
Insp Anne Higgins said the initial group of children congregated at the Cullompton Community Association fields, but it dispersed as police units arrived at the scene.
During searches officers also found a heavy metal crank in one bag.
A 17-year-old youth received a verbal warning for the possession of cannabis, and cigarettes were taken from numerous children.
Police said the arrangements appear to have been made on the social networking website Bebo and by emails, mobile phones and text messages.
Bebo said it had not been contacted by the police about the matter.
A spokeswoman said: "We would, of course, assist immediately with any investigation.
The head teachers of two local schools have declined to comment.
Insp Higgins said police would not tolerate this type of behaviour, which not only had the potential to become very serious, but also undermined public safety.
"Any attempt to repeat such a gathering will be subject to the full use of police powers under public order legislation, including the stop and search of people within a five-mile radius of any potential location for disorder," she said.
The inspector said the force would consider applying for dispersal orders if necessary.
She said it was important parents were aware of their children's whereabouts to prevent them becoming involved in crime and disorder.
"Very few parents actually attended the location to collect or deal with their children," she said.
"This is very disappointing and of major concern."
Police said numerous school-aged youths were still out until the early hours of Sunday morning.
Officers dealt with five missing persons reports in Cullompton - four of whom were found to be involved in the potential disorder.