British police clashed with rioting youths in a third day of unrest sparked by a police shooting last week.

Groups of young people attacked police and broke into shops Monday, after some of the worst rioting over the weekend in London in years. Media reports said the latest violence began when police tried to carry out a stop-and-search operation.

British authorities say at least 215 people have been arrested in the city and around 35 police officers injured — including three hit by a car while trying to make arrests in northeast London.

British Deputy Prime Minister Nick Clegg described the violence and theft as “needless,” “opportunistic” and “completely unacceptable.” Home Secretary Theresa May condemned the riots as “sheer criminality.”

The violence broke out after the death of a local 29-year-old man in a police shooting in London's depressed Tottenham neighborhood on Thursday. Two days later, a peaceful demonstration held to mark his death turned violent by Saturday evening, with protesters throwing stones at police, smashing store windows and setting fire to cars. Several buildings and a double-decker bus also were set ablaze.

Police said the violence spread to other parts of the city Sunday night and early Monday in what they called “copycat criminality.”

But analysts say last week's death in Tottenham was a trigger for what is already a volatile situation, with government austerity measures aimed at reducing Britain's debt taking a toll at the local level.

Some residents say the riots were spurred by anger over the gloomy economic situation in north London, specifically high unemployment and reduced public services.

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

In 1985, a police officer was hacked to death there when Afro-Caribbean youths in a deprived housing estate went on a rampage.

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