Three people have been arrested on suspicion of taking part in a series of street fights which attracted a crowd of some 200 teenagers in Walthamstow, northeast London, on Tuesday night.
Metropolitan police said on Wednesday that a 16-year-old boy and a 16-year-old girl had been arrested on suspicion of affray, while an 18-year-old man was arrested on suspicion of violent conduct.
All three were remanded in custody in police stations in east London.
There is an increased police presence in the area today and a dispersal order is in place.
Police said no one was injured, but violent scenes, showing teenagers armed with baseball bats, were posted to Twitter last night.
A crowd began to gather at around 5pm on Tuesday, around Hoe Street and Walthamstow tube station, and police said it was dispersed at 8:45pm.
Posts on social media, which could not be verified, said that the original disturbance was caused by a disagreement between two local girls from different colleges, supposedly over a boy.
It appears that rumours of fighting had made their way through the local schools and colleges – by 7pm a throng had gathered to see what was going on.
Police said that the vast majority of those present were just there to watch what was going on and film any action on their phones.
By 8:40pm, police said arrests had been made and the group dispersed.
But this video, posted at 9:12pm, shows more violence and a heavy police presence.
And this one, posted at 10:39pm, shows yet more fighting, which spilled over into a supermarket.
Hair weaves could be seen on the floor in the aftermath of the violence.
Jon Simpson, the Met's chief inspector for Waltham Forest, said in a statement:
We are providing additional high visibility policing patrols in the area to reassure local residents and businesses and to ensure that there is no repeat of last night's disturbance.
We are working closely with our colleagues at Waltham Forest Council and local schools to identify those responsible for any criminal acts.
The vast number of children who congregated in the area yesterday were merely there to watch and film on their phones rather than to participate in any criminal activities.
An investigation into the circumstances of the incident by detectives from Waltham Forest Borough is ongoing.