MELBOURNE (AFP) - Australian Open officials admit violence is nearly impossible to eradicate despite unprecedented security following the third ethnic clashes here in as many years. Tournament director Craig Tiley said it was hard to stop every incident, with organisers concentrating on preventing as many as possible and stamping out any flare-ups quickly. "It is hard to have people walk through the site in large numbers and not to have an incident between three or four individuals, but our action against that is swift and quick," Tiley told AFP. Hundreds of thousands of fans pass through Melbourne Park over the two-week tournament with many gulping beer at the Garden Square big-screen area where Serbian and Bosnian fans brawled on Friday. They hurled plastic chairs at each other, knocking one Bosnian woman to the ground as she was hit on the head. About 30 men were ejected as skirmishes continued outside. The latest incident came despite increased CCTV surveillance after similar clashes over the past two years. In 2007, Serbian and Croatian fans attacked each other with flag poles and bottles and last year, police used pepper spray to subdue rowdy elements of the crowd watching a match between Konstantinos Economidis and Fernando Gonzales. Tiley said nearly all of Melbourne Park, which includes three main arenas, two show courts and 19 outside courts on the edge of the city centre, was now covered by CCTV cameras which are monitored constantly. "If we recognise someone that is potentially going to de disruptive, through the CCTV we monitor what they're doing and how they're moving through the site," he said. "We have a full security team that's constantly looking at surveillance tape and direct TV. If they recognise something that's going to be potentially disruptive they go through a management process with that." Tiley admitted the incidents had damaged the image of the tournament, which is the only Grand Slam - and the only tennis event - to have a problem with violence. But he said they would not harm Melbourne's chances of retaining the Open, which has reportedly attracted interest from Sydney, Shanghai and Dubai. "It's certainly damaged the image (but) we've been consistent in saying we've no intention of going anywhere," Tiley said. "Melbourne is the home of the Australian Open. It's supported not only by our national visitors but also the visitors from outside the state of Victoria." The latests incident attracted strong condemnation from players such as Roger Federer, Ana Ivanovic, Mario Ancic and Bosnian-American Amer Delic, whose defeat to Serbia's Novak Djokovic preceded the violence. Melbourne, Australia's second biggest city, is a cultural melting pot and home to thousands of Serbs, Bosnians and Croatians who are sometimes at odds over the 1990s Balkans war.