British Prime Minister David Cameron will deploy 16,000 police officers on Tuesday, almost tripling the current number, to help quell the London riots.

Cameron cut short a vacation in Italy to return to London where he called for an emergency parliamentary session on Tuesday where he made the announcement after three nights of fire and looting in the capital and other British cities.It is believed that gangs of youths, some masked, are the ones looting shops, setting businesses ablaze and clashing with police in neighborhoods across London.

The first riot broke out in Tottenham on Saturday, where protestors clashed with police outside a station, as they were demanding justice for the Thursday shooting of 29-year-old Mark Duggan after police stopped a minicab he was driving in.

Since then, the riot has spread to at least six other parts of London to include the cities of Liverpool and Birmingham by Monday night.

Reuters has reported that politicians and police blamed the London riots, which is the worst in decades, on criminals and opportunistic hooligans. However, residents in the affected areas and some commentators paint a different picture and have attributed the unrest to local tensions and anger over economic hardship in a city where there is a growing gap between the haves and have-nots.

Social media such as Twitter have been helping to increase the number of rioters, who have been reported to be using the tool as a means to disclose meeting points, overwhelming the London Metropolitan Police, which have already deployed some 6,000 riot police to the hot areas.

"This is criminality pure and simple," Cameron told reporters outside his Downing Street office. "People should be in no doubt that we will do everything necessary to restore order to Britain's streets." 

Though he upped the manpower, Cameron stopped short of sending in the army or deploying water cannons against the rioters.

More than 450 arrests have been made since the start of the riots on Saturday and authorities have said the prisons in London were already reaching capacity. The newly detained are being shuttled to jails outside the capital, according to the Washington Post.

British leaders will be back in parliament on Thursday for more riot discussions.