Two people are injured in the clash involving up to 100 young people, many of them wearing school uniforms.
Police have made seven arrests after a mass street brawl involving up to 100 people, many of them schoolchildren still in uniform.
Two people were taken to hospital with what police described as “non-life threatening injuries”.
Those arrested were aged between 15 and 21.
The trouble started on Monday evening in Northumberland Heath, Bexley, south London.
Police said they were called to a “large fight between a group of youths”, an hour after a disturbance more than a mile away in Bexley Broadway.
Local resident Jeanne Asquith said she had never seen anything like it in the eight years she had lived in the area.
“I just hope the schools deal with those involved,” she wrote on Facebook. “Most were wearing school uniform!”
Chief Superintendent Jeff Boothe said there would be extra police patrols in the area on Tuesday.
“This incident was a large scale fight in a public area and would have been shocking to anyone who witnessed it,” he said.
“In total over 40 calls were made to police by members of the public and a number of incidents occurred across at least five different locations.
“Every available officer within Bexley was deployed to assist with the incident and support from the Territorial Support Group was provided.”