LONDON - In the battle to bring calm to the British streets, authorities are playing both sides of technology - employing facial recognition software to hunt suspects while at the same time considering restrictions on social media the government claims has been used as an organizing tool for rioters.
Officers are feeding photographs of suspects through Scotland Yard's newly updated face-matching program, which has been under consideration for London's 2012 Games.
A law enforcement official, who spoke to the Associated Press on condition of anonymity, said that facial recognition is one of many tools police are using to hunt suspects still at large. Other techniques include posting headshots to photo-sharing site Flickr and old-fashioned public appeals.
A spokesman for Scotland Yard confirmed Thursday that facial recognition technology was at his force's disposal.
Meanwhile, Prime Minister David Cameron said the government, police and intelligence services were looking at whether there should be limits on the use of social media sites like Twitter and Facebook or services like BlackBerry Messenger to spread disorder.
Government officials said they were discussing with spy agencies and communications companies whether messaging services could be disabled in specific areas, or at specific times.
Authorities are considering "whether it would be right to stop people communicating via these websites and services when we know they are plotting violence, disorder and criminality," Cameron said.
"Police were facing a new circumstance where rioters were using the BlackBerry Messenger service, a closed network," to organize riots, he said. "We've got to examine that and work out how to get ahead of them."
Cameron promised vigorous and wide-ranging measures to restore order and prevent riots erupting again on Britain's streets including also taking gang-fighting tips from American cities.
Cameron told lawmakers there would be no "culture of fear" on Britain's streets, as police raided houses to round up more suspects from four days of rioting and looting in London and other English cities. He said the government was "acting decisively" to restore order after the riots, which shocked the country and the world.
Cameron said authorities were considering other new powers, including allowing police to order thugs to remove masks or hoods and evicting troublemakers from subsidized.
"We will not allow a culture of fear to exist on our streets," Cameron said. "We will not let a violent few beat us."
Lawmakers were summoned back from their summer vacations for an emergency session of Parliament in the riots as government and police worked to regain control, both on the streets and in the court of public opinion. Calm prevailed in London overnight, with a highly visible police presence watching over the capital, but tensions remained high across the country.
Cameron promised tough measures to stop further violence and said "nothing should be off the table," including water cannons and plastic bullets.
He said riot-hit businesses would receive help to get back on their feet, and promised to look to the United States for help in fighting the street gangs he blamed for helping spark Britain's riots.
Cameron told lawmakers that he would look to cities like Boston for inspiration, and mentioned former Los Angeles and New York Police Chief Bill Bratton as a person who could help offer advice.
He said he wanted to look at cities including Boston and Glasgow that had fought gangs "by engaging the police, the voluntary sector and local government."
"I also believe we should be looking beyond our shores to learn the lessons from others who have faced similar problems," Cameron said.