THEY hang around street corners, shopping malls and train stations looking for trouble and victims.
They rob children as young as 10 - taking mobile phones and even designer shoes.
They bash teenagers and scour the suburbs for parties to rash or rival teens to fight.
These are Sydney's street gangs. No one knows how many there really are, but there are fears of hundreds, and most suburbs have at least one.
Many disband as quickly as they form, but members of others graduate to be serious criminals and are used as "feeder" groups for adult gangs such as bikies and drug syndicates.Teenagers in the western suburbs and inner-city have started local chapters of the violent Bloods and Crips.
Social networking sites are fuelling the trend with more and more young people joining gangs or starting up new ones.
Websites are full of images dedicated to local gangs such as F.B.I (Full Blooded Islanders) and the Mounty County (local Mount Druitt gangs).
Gatecrashing is increasingly becoming a problem - brought on by social networking, through which gangs communicate.
"Police have concerns about street groups adopting names and mannerisms of what are violent organised criminal groups in overseas countries," Deputy Police Commissioner Nick Kaldas said.
"Each local area command has identified groups of youths within their area who have formed an association using particular names to give themselves a group identity. These are not organised criminal enterprises. They are based on social interaction but they can and do engage in anti-social behaviour and do come to the notice of police far too often for crimes such as petty theft, graffiti, vandalism and street fights.
"Police have gathered good intelligence on these groups and community members have been active in assisting police identify ring leaders and track the activities of these groups. Groups tend to identify along geographic lines.
"Police have adopted an escalation model which allows police to respond appropriately. This could be a LAC response for street level activity or additional specialist resources can be called upon in the case of identified criminal groups."'
He said police realised that some groups were not just street gangs breaking street lights and singled out the Muslim Brotherhood Movement as a serious concern.
"NSW Police believe the Muslim Brotherhood Movement is a more serious enterprise than the streets groups. The MBM attracts disenfranchised youth who can be drawn to more sophisticated criminal groups for the lifestyle, the element of belonging, money and power they believe this brings."
Investigation unearthed more than 50 gangs on the internet alone and experts said there would be hundreds more.
"It is becoming trendier to join gangs," former assistant police Commissioner Clive Small said.
"A number of years ago a state intelligence report for NSW police put the number of street gangs well over 200 and there would be more now." Mr Small said many gangs were just "young hoodlums" out to make trouble. "But others grow into serious criminals who become part of the organised criminal network," he said.
The influx of new Australians from the Pacific Islands, and parts of Africa such as Somalia and Sudan have added to the problem.
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Gangs locked in bloody turf wars
WHEN you grow up in some of Sydney's toughest neighbourhoods, street gangs give a sense of power, identity, pride and protection in areas where those same things are in short supply.
But most of all, according to the young gang members who've shared startling insights to this dangerous subculture, the brotherhood these young men share with fellow gang members is all about "turf".
The bond of a postcode in Sydney's toughest suburbs is stronger than any ethnic or family tie.
"No matter what gang you are, whether Bloods or Crips, when it comes to turf, that's where it all matters," says Kage, 18, one of the leaders of Gang Grey and a central figure in the feud that erupted 10 days ago into a bloody brawl amid shocked shoppers at Westfield Mt Druitt.
"Fighting is my life. If I died fighting I'd die happy," said Kage, who fell in with the gang when he started high school.
"I've been shot at, I've been stabbed, I've been hit with a machete; that's the thing about us, too much pride."
While the local gangs are usually content battling each other, the ongoing feud with Gee-40 and other groups from the Parramatta area - which he admits goes back so far "no one remembers how it started" - has resulted in a motley alliance.
Mounty County is a loose coalition of gangs from the the Mt Druitt area, widely regarded as the main proving ground for the next generation of thugs.
"This is our home, when other gangs come here we have to do everything to protect our home," Kage said. "It doesn't matter if you're FOB [fresh off the boat], Aussie, Leb, it's all about area."
Much of the action now happens online, with social networking sites like Facebook and YouTube used to threaten rival gangs.
Former gang leader Jonathon Walker, 24, has the scars from stab wounds to his head, shoulder and stomach - which required more than 80 stitches - to remind him of the six years he spent with Blacktown-based Nocturnal.