The BBC's Ben Ando says there is a "tense stand-off" between police and protesters
Petrol bombs have been thrown at police and a shop, two patrol cars and a bus set on fire in a disturbance in Tottenham, north London.
The incident began after a protest over the fatal shooting of a young man by police on Thursday turned violent.
Tottenham MP David Lammy says it is "important our community remains calm" after a man was shot dead during an operation by police. A friend of Mark Duggan told Channel 4 News there may be unrest.