Police in London have arrested at least 40 people after the worst riots the city has seen in years.

Extra police were on duty Sunday in north London's depressed Tottenham neighborhood, the scene of Saturday night riots that were sparked by a fatal police shooting of a local resident. Officials say 26 police officers were injured in the riots.

The area was quiet, but tense, a day after the unrest. However, new trouble broke out in Enfield, just north of Tottenham late Sunday. TV footage showed the windows of some shops that were smashed, and a police car that was damaged. Riot police were brought in to guard against any further damage.

In Saturday's violence, a peaceful protest over the killing of a 29-year-old man by police earlier in the week escalated, with protesters throwing stones at officers, smashing store windows and setting cars on fire. Several buildings and a double-decker bus also were set ablaze.

Some residents told reporters the riot is the result of long-simmering anger about the gloomy economic situation in north London, with high unemployment and reduced public services.

Tottenham is home to a large number of ethnic minorities and has a history of racial tensions.

It was the scene in 1985 of one of the most violent riots in Britain's history in which a police officer was hacked to death when Afro-Caribbean youths in a deprived housing estate of Tottenham went on a rampage.

The latest riot comes as London prepares to host the 2012 Olympic Games. London Mayor Boris Johnson sought to assure the world that the city is safe.