A number of revellers have been arrested as riot police were pelted with bottles, chairs and a suspected petrol bomb as they tried to close down an illegal rave.
Trouble erupted on Halloween night in central London as hundreds of people attempted to get into a rave in Lambeth, central London.
After three hours at the scene police said the situation is "very much ongoing" as they deal with public disorder and criminal damage.
It is not yet clear how many people have been arrested. Four police officers have been treated at the scene for minor injuries.
Crowds first gathered on Black Prince Road at Albert Embankment, before dispersing down Lambeth Road on to Lambeth High Street and nearby Whitgift Street.
Police said they had posted officers at junctions to Whitgift Street to "to prevent any escalation" of the trouble.
But footage from the scene showed an angry mob throwing objects at police lines as they chanted "scum" and "pigs".
Bangers have also been thrown, a male was seen letting off a fire extinguisher and bins have been set alight on some surrounding streets.
Riot police, with dogs and shields, were seen drawing their batons against a charging crowd.
An event called Scumoween: A Nightmare On Scum Street had been advertised on Facebook to take place in Whitgift Street beginning at 8pm on Halloween night and lasting all weekend.
Of 13,000 invited guests on the social networking site, 4,000 said they planned to attend.
The free event was due to feature music "from the full spectrum of underground dance".
In a warning on Wednesday to those due to attend, organisers Scum Tek said: "This party is going ahead, stay peaceful, stay calm. Patience and numbers is in our favour. Do not antagonise the police. We don't need to. At the end of the day we want to leave them remembering our good attitudes, we just came to dance, we are not their enemy."
Organisers encouraged people to "keep coming" and "don't give up" at around midnight when trouble flared, but police advised people not to go to the area.
The Met tweeted: "We would discourage anyone still thinking of attending the illegal rave in Whitgift Street from coming to the area due to ongoing police op."
Residents in Lambeth told of their frustration at the disruption overnight into Sunday.
Rhodri wrote on Twitter: "They're now gathering on my street. There are families here with young kids that don't deserve this disruption."
Christopher Kilby said: "I won't be getting much sleep tonight. Chants of 'we want scum' still ringing loudly as protesters continue to confront police."
Two hours later he added: "I'd really like to go to sleep now. Could the rioters please just give up and go home?!"
Police said criminal damage had been caused to private vehicles and property in the area.