Crowds attacked riot police and set two squad cars alight in north London on Saturday following a protest at the fatal shooting of a man by armed officers earlier in the week.
Disorder spread after up to 200 people gathered near Tottenham police station during the evening.
The Metropolitan force said bottles were thrown at officers on a foot patrol and one of the vehicles was pushed into the middle of the main road before it was set on fire.
Riot police sent to the scene came under attack from a crowd throwing bottles and missiles, said the force.
"It's very much an ongoing situation," a police spokesman said. No officers are reported to have been injured.
The earlier protest was held over the shooting of a 29-year-old man who was killed after an exchange of gunfire with police on Thursday.
The man had been in a taxi when it was stopped by armed officers as part of a pre-planned operation. One policeman escaped unhurt after a bullet struck his radio.
"It's really bad," local resident, David Akinsanya, 46, told the BBC.
"I'm feeling unsafe ... I saw a guy getting attacked. There seems to be a lot of anger in Tottenham tonight ... as I left they were starting to attack the police station."
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