* Cameron pledges tough action to quell unrest
* Says targeting street gangs a national priority
* Acknowledges police initially caught on hop
* Police reinforcements keep London relatively peaceful (Recasts, adds more Cameron quotes, background)
By Matt Falloon
LONDON, Aug 11 (Reuters) - Prime Minister David Cameron vowed on Thursday to hunt down the street gangsters and opportunistic looters he blamed for Britain's worst violence in decades, and acknowledged that police tactics had failed at the start of the rioting.
"The fightback has well and truly begun," the Conservative leader, grappling with a defining crisis of his 15-month-old premiership, told an emergency session of parliament.
"As to the lawless minority, the criminals who've taken what they can get, I say this: We will track you down, we will find you, we will charge you, we will punish you. You will pay for what you have done," Cameron said.
Closed-circuit TV footage would be used to identify culprits, he said, vowing to let "no phoney human rights concerns" about publishing the pictures obstruct the effort.
British leaders are concerned that the rioting could damage confidence in the economy and in London, one of the world's biggest financial centres and venue for next year's Olympics.
Cameron is under pressure to ease austerity plans, toughen policing and do more for inner-city communities, even as economic malaise grips a nation whose social and perhaps racial tensions exploded in four nights of bewildering mayhem, first in the capital and then other major cities.
The initial police response was inadequate, Cameron said. "There were simply far too few police deployed onto the streets. And the tactics they were using weren't working."
Defending planned police funding cuts against criticism from opposition Labour leader Ed Miliband, Cameron also proposed more police powers, including the right to demand that people remove face coverings if they are suspected of crime.
Hugh Orde, President of the Association of Chief Police Officers, said this week a 20 percent cut in police funding over the next few years until 2015, planned by the Conservative-Liberal Democrat coalition, would pose great challenges.
"I do sense without question resentment (among police officers) that they are now being portrayed in the routine as corrupt, unprofessional and need sorting out," he told Reuters.
Cameron, who has already authorised police to use baton rounds and water cannon where necessary, said he would also explore curbs on the use of social media tools if these were being used to plot "violence, disorder and criminality".
The British leader said he would keep a higher police presence of 16,000 officers on London streets through the weekend and would consider calling in the army for secondary roles in future unrest to free up frontline police.
He denied that deprivation had caused the problem, saying: "This is not about poverty, it's about culture. A culture that glorifies violence, shows disrespect to authority, and says everything about rights but nothing about responsibilities."
Cameron promised to compensate people whose property was damaged by rioters, even if they were uninsured. The riots will cost insurers more than 200 million pounds ($320 million), the Association of British Insurers estimated.
PUBLIC FURY OVER LOOTING
Many Britons were appalled at the scenes on their streets, from the televised mugging of an injured Malaysian teenager to a Polish woman photographed leaping from a burning building, as well as the looting of anything from baby clothes to TV sets.
But occupying the moral high ground is tricky in a country where some lawmakers and policemen have been embroiled in expenses and bribery scandals, and top bankers take huge bonuses even as the taxpayer bails out financial institutions.
Cameron had ordered a rare recall of parliament from its summer recess to debate the unrest which flared first in north London after police shot dead an Afro-Caribbean man. That disturbance then mutated into widespread looting and violence.
The prime minister said criminal street gangs were at the heart of the violence. "Territorial, hierarchical and incredibly violent, they are mostly composed of young boys, mainly from dysfunctional homes," he added.
Arguing that police, local government and voluntary workers needed to work together to stop inner-city street gangs, as they had in American cities such as Boston, he said: "I want this to be a national priority."
Cameron, who waited two days before returning from holiday to deal with the crisis, has denied the unrest was linked to planned government spending cuts, mostly not yet implemented.
But community leaders say inequality, cuts to public services and youth unemployment also fed into the violence in London, Birmingham, Manchester and other multi-ethnic cities.
As the clear-up proceeds, the Conservative-Liberal Democrat coalition government must find quick fixes to avoid further unrest while also addressing longer-term problems.
London police staged new raids on apartments on Thursday recovering looted designer clothes and iPods.
A surge in police numbers helped calm streets on Wednesday night, but previous episodes of often unchecked disorder have embarrassed the authorities and exhausted emergency services.
Businessmen and residents had come together to protect their areas. Police in some areas complained vigilantes were only complicating their task and asked people to stay at home.
Police have arrested more than 1,200 people across England, filling cells and forcing courts to work through the night to process hundreds of cases. Among those charged were a teaching assistant, a charity worker and an 11-year-old boy.
The local council in Lewisham, south London, sent out a text message to residents reading: "Do you know where your children are?" -- although in some cases parents had joined the looting alongside their offspring.
Cameron's view of the rioters as thrill-seeking thugs who are indicative of a breakdown in Britain's social fabric and morals has struck a chord with many people.
Others point to chronic tensions between police and youth, a dearth of opportunities for children from disadvantaged areas and visible inequalities where the wealthy often live in elegant houses just yards away from run-down city estates.
Social strains have grown in Britain for some time, with the economy struggling to clamber out of an 18-month recession, one in five young people out of work and high inflation squeezing incomes and hitting the poor hardest.
The crisis has also exposed Britain to opportunistic attack or ridicule from countries stung by frequent Western criticism of their human rights records and who now scent hypocrisy.
Iran's hardline Kayhan newspaper likened the British riots to Arab protests against autocrats, saying the "tumult against illegitimate rule ... has found its way to the heart of Europe".
State media in Libya have also depicted the British unrest as legitimate protests born of social deprivation.
Libyan state television said Cameron was using Irish and Scottish "mercenaries" to tame the riots in English cities. ($1 = 0.619 British Pounds) (Additional reporting by Adrian Croft, writing by Alistair Lyon, editing by Peter Millership)