LONDON (AP) - Thousands more police officers flooded London streets Tuesday in a bid to end Britain's worst rioting in a generation as nervous shopkeepers closed early and some residents stood guard to protect their neighborhoods. An eerie calm prevailed in the city, but unrest spread across central and northern England on a fourth night of violence driven by poor, diverse and brazen crowds of young people.
Scenes of ransacked stores, torched cars and blackened buildings frightened and outraged Britons just a year before London is to host the Summer Olympics and brought demands for a tougher response from law enforcement.
London's Metropolitan Police department put thousands more officers on the streets and said that by Wednesday, there would be 16,000 - almost triple the number present Monday. The department said a large presence would remain in the city through the next 24 hours at least.
Britain's riots began Saturday when an initially peaceful protest over a police shooting in London's Tottenham neighborhood turned violent. That clash has morphed into a general lawlessness in London and several other cities that police have struggled to halt with ordinary tactics.
The show of strength by police appeared to have quelled unrest in London late Tuesday, but in a move that could raise tensions, a far-right group said about 1,000 of its members around the country were taking to the streets to deter rioters.
Outside of London, chaos continued to spread.