London police on Sunday maintained an uneasy calm as night fell on the area the day after some of the capital's worst rioting in years, sparked by the fatal shooting of a local man.

As the sun set Sunday, Scotland Yard reported that youths had vandalised a police car and smashed two windows in Enfield, a suburb three miles north of Tottenham, the area at the centre of the previous night's disorder.

Additional police resources were deployed in the volatile neighbourhoods on Sunday as the Metropolitan force vowed to avoid a repeat of the earlier scenes of mayhem.

Homes were torched and shops looted late Saturday, conjuring up memories of 1985 riots in the same area and dampening the mood in a city hosting the Olympic Games in a year.

Police said 26 of its officers were hurt, while three members of the public also needed treatment following the surprise violence. By Sunday, all the injured police officers had been discharged from hospital.

A total 55 arrests were made, while Prime Minister David Cameron's office described the rioting as "utterly unacceptable."

A spokesman for the London Fire Brigade said all the fires were under control.

"We are still at the scene of some of them to damp them down and make sure everything is out," he added, as burnt-out cars and buildings in sealed-off roads bore witness to the night before.

The mayhem, which broke out in Tottenham just before sunset on Saturday, followed a protest over the death of a 29-year-old man last Thursday during an apparent exchange of gunfire with police.

Thursday's killing of Mark Duggan, a father-of-four, was "absolutely regrettable," police commander Adrian Hanstock said in a statement, adding that an investigation into the shooting was underway.

According to the Guardian newspaper, initial ballistics tests on a bullet which was found lodged in a police officer's radio when Duggan was shot revealed it was a police issue bullet, raising doubts over the early explanation of events.

Duggan's brother Shaun Hall called for peace.

"We're not condoning any kind of actions like that at all," he told Sky News.

"I know people are frustrated, they're angry out there at the moment, but I would say please try and hold it down. Please don't make this about my brother's life, he was a good man."

Saturday's demonstration had begun as a peaceful rally outside the police station on Tottenham High Road before two police cars were attacked with petrol bombs and set ablaze.

A double-decker bus was then torched as the violence rapidly spread, with gangs of hooded youths descending on the area.

There was concern that the unrest was fuelled by rapid posts on social media sites inciting others to join in.

London has seen student and trade union protests turn ugly in the last 12 months but this outbreak of rioting was the worst seen for years away from the capital's centre.

"The rioting in Tottenham last night was utterly unacceptable," a Downing Street spokesman said in a statement.

One witness said Saturday's scene resembled the Blitz, or when parts of London burned following German bombing in the Second World War.

"So many people have lost everything. It's just crazy. It looks like it's the Second World War. It looks like the Blitz where we were living," Tottenham resident Stuart Radose told Sky News television.

London Mayor Boris Johnson said Sunday he had no plans to cut short his holiday to return to the capital, adding he had "full confidence" in the police.

The area is an ethnically-diverse urban area best known for its football club Tottenham Hotspur.

"This is an attack on Tottenham, on people, on ordinary people," local member of parliament David Lamy told reporters.

"Women who are now standing on the streets homeless. These are ordinary shop keepers who live above their shops."

Duggan was killed when specialist firearms officers stopped a minicab in which he was travelling to carry out a pre-planned arrest.

The Independent Police Complaints Commission, which investigates all police shootings, said they were accompanied by officers from Trident, the unit focused on tackling gun crime in the black community.

The march against Duggan's death began at Broadwater Farm, a 1960s public housing estate in Tottenham that is notorious across Britain.

In 1985, police constable Keith Blakelock was hacked to death on the estate in some of the worst urban rioting in Britain during the past 30 years.