Violence flared in Liverpool for up to five hours overnight as rioters took to the streets in the south of the city.
Cars and wheelie bins were set alight during the disturbances, which spread from the city centre to Toxteth, Dingle and Wavertree.
The disorder started at about 22:00 BST and had calmed down by about 03:00 BST.
There were hundreds of youths on the rampage on the streets. Merseyside Police said they had arrested six people overnight.
Andy Ward, Merseyside Assistant Chief Constable, said the violence was a "copycat issue", as London saw its third night of rioting.
Two officers hurt
"It is a very saddening picture to be honest," he said.
"We had a situation last night where a number of young people decided to gather and they have decided to go on a spree of disorder and violence across parts of south Liverpool."
He said the youths had organised themselves on social networking sites, which he conceded made the force's job more difficult.
Mr Ward said police officers were attacked with two suffering injuries to their legs.
The windows of Admiral Street police station were smashed in.
The force tried to contain the troublemakers rather than get involved in running battles.
As the night progressed, the group became more fragmented as officers in riot gear and wielding batons, supported by police vans, sealed roads off.
However, there were several stand-offs as rioters pelted officers with missiles, from golf clubs to bricks and bottles.
Smithdown Road, Upper Parliament Street, Lodge Lane, Lawrence Road, Princes Road and Princes Avenue were badly hit.
'Tesco store looted'
A van was set alight in High Park Street and the windows smashed at Mount Carmel Social Club.
The rioters also scattered bins across the road, setting them alight, to try to stop police pursuing them.
The Tesco Express store in Myrtle Street was looted - with some of the raiders said by witnesses to be as young as 10 years old.
Homes do not appear to have been damaged and there were no reports of injuries.
Mr Ward said Merseyside Police had been prepared, but the force had not expected disorder on such a scale.
Residents referred to the violence as "madness" and "senseless".
One said: "This has been waiting to kick off for a while". The resident added that there were fears the same could happen again on Tuesday evening.
Mr Ward said: "Tonight we will have a very robust response to events that take place."
Deputy Chief Constable of Merseyside Police, Bernard Lawson, said his officers had to deal with a very difficult situation, but that it was "the result of a small minority of young people engaged in criminal activity".
He said the aim of last night's policing operation was to "contain the violence" that suddenly escalated in order to ensure the safety of the public.
Police have also appealed to the communities affected by the riots to come forward with any images, photographs or mobile phone footage of any criminal incidents.
Joe Anderson, leader of Liverpool City Council, said: "We deplore in the strongest terms the street violence and criminality which took place around the city centre and parts of south Liverpool last night."
He said the city was "functioning as normal" despite these incidents.
A spokesman for Liverpool One shopping centre said there had been disturbances at two shops at about 02:00 BST but no-one was injured and the trouble was quickly dispersed.
People have been taking part in a spontaneous clean-up in Toxteth. It included Labour councillor Steve Munby, the city council's cabinet member for neighbourhoods who represents Toxteth.
He said he believed the riots were led by a "small group of organised criminals" from outside the Toxteth area. Their main aim was to "loot and rob", he said.
Mr Munby said a huge amount of effort had been put into improving relations between the police and the community since the riots in 1981.
Sonia Bassey-Williams, 45, helped organise this year's 1981 Toxteth Riots - 30 Years On exhibition at Liverpool's International Slavery Museum.
She said the violence was a reaction to the government cuts which were leaving more people in poverty.
"I think people just react out of frustration in this way," she said.
But she agreed with other people who said a "criminal element" were using it as an excuse to cause mayhem and to loot.
She added: "I think the government needs to sit up and listen. I just hope people start a dialogue pretty quickly to try and bring some calm back to the community."
Alan Dean, councillor for the Princes Park ward in Liverpool, said it was "a campaign orchestrated very early on".
He said it was organised through social media websites and Blackberry Messenger.
He said "It's just sheer, unadulterated mindless violence and thuggery. There's no benefit to anybody with this."