London riots: British PM David Cameron vows to quell violence

(CBS/AP) LONDON - Britain will not let a "culture of fear" take over its streets, said Prime Minister David Cameron on Wednesday. He also said police have drawn up contingency plans to use water cannon if necessary to remove rioters from the streets.

Pictures: Tottenham riots lead to 160 arrests

Thousands of extra police officers on patrol kept a nervous London quiet Tuesday after three nights of rioting. However, looting flared up in Manchester and Birmingham, where a murder probe was opened after three men were killed in a hit-and-run reportedly as they took to the streets to deter potential rioters.

"We will do whatever is necessary to restore law and order onto our streets," Cameron said in a somber televised statement. "Nothing is off the table" - including water cannon, commonly used in Northern Ireland but never deployed in mainland Britain.

Cameron has recalled Parliament from its summer recess for an emergency debate on the riots Thursday.

Meanwhile, hundreds of shops were shutdown early or boarded-up on Tuesday night as a precaution.  In spite of this, unrest spread across England on a fourth night of violence by brazen crowds of young people. Scenes of ransacked stores, torched cars and burned-out buildings have frightened and outraged many residents.

The chaos in England comes just a year before the country is to host next summer's Olympic Games. Now, the world is closely watching the country's response to the violence. Police across the country have made almost 1,200 arrests - including 800 in London - since the violence broke out in the capital on Saturday.

In east London's Bethnal Green district, convenience store owner Adnan Butt, 28, said the situation was still tense.

"People are all at home - they're scared," he said.