LONDON - Parts of the British capital resembled a battleground, with burnt-out buildings, scattered debris and rampaging gangs, after a third night of rioting on Monday.

A number of areas in the British capital were hit by the rioting on Monday night, including Peckham, Clapham, Hackney and Ealing. Violence had also spread to Birmingham, Bristol, Liverpool and Nottingham.

Politicians, including British Prime Minister David Cameron, abruptly ended their holidays and returned to London. Parliament has been recalled for an emergency session on Thursday to debate the riots.

Analysts urged London's Metropolitan police to "readjust" planning for the Olympic Games, due to start in less than a year.

"We will do everything necessary to restore order to Britain's streets and make them safe for the law-abiding," Cameron said in Downing Street on Tuesday after a meeting of the government's emergency committee.

More than 16,000 officers will be on London's streets on Wednesday, he said. All police leave in London has been canceled.

Scotland Yard said that 525 people have been arrested in London after three days of "unprecedented" rioting.

Cameron condemned what he called the "sickening scenes of people looting, vandalizing, thieving, robbing".

Fresh riots erupted in Hackney in north London on Monday afternoon, after police stopped and searched a man but found nothing.

Within a few hours, rioters looted shops, set alight vehicles and buildings, and attacked police officers in Croydon in the southeast, Lewisham and Peckham in the south, Camden and Chalk Farm in the north, as well as Ealing, a well-off area in west London.

In Hackney, rioters, easily outnumbering police officers, smashed the windows of Ladbrokes, a betting shop, and buses parked near Hackney Central Station.

Then rioters, wearing hooded tops, broke into a van and took out wooden pallets to use them as weapons to attack the police and smash shop windows.

Gangs also looted a Texaco petrol station and a Spar food store in the main street of Hackney.

Acting Scotland Yard Commissioner Tim Godwin, Britain's most senior police officer, called on parents and guardians to keep youngsters in at nighttime and urged the public to stay off London's streets.

"There are far too many spectators who are getting in the way of the police operation to tackle criminal thuggery and burglary," he said.

In the tense atmosphere media workers also became targets, with photographers and cameramen fending off rioters to protect their equipment.

Hackney residents expressed concern about the security situation in their borough with the Olympic Games looming.

Hackney, one of the traditionally less well-off areas of the British capital, will be hosting Olympic events.

"It looks like the police cannot control the situation today. But there will be significantly more people coming to Hackney next summer," said 22-year-old university student Naveed Ahmed on Monday. His family moved from Pakistan to Hackney decades ago.

Preparations for the Games, however, will not be affected by the riots, according to the British Olympic Association (BOA).

BOA Director of Communications Darryl Seibel told Sky News that he was confident that the Games would pass off safely.

But Pepe Egger, who works at Exclusive Analysis, a political risk think tank, said the police "might be challenged and overstretched if something like this happens" during the Games.

"I don't think they were necessarily planning for this kind of event, on this kind of scale," Egger said. "I would assume that probably they didn't anticipate the speed, the volume, and the scale of this kind of event. Now they'll have to readjust their planning for the Olympics.

"The problem for the police will be if there's the Olympics, rioting like this, and a terrorist attack, then they couldn't cope," he said.

The rioting that has rocked London over the last three days started after a peaceful protest on Saturday following a fatal police shooting last week.

The protest in Tottenham on Saturday was followed by violence that has escalated.

A 26-year-old man who was shot in a car in Croydon, south London, during disturbances this week has died, becoming the first fatality of riots sweeping Britain, police said on Tuesday.

Agencies contributed to this story.