MELBOURNE, Australia -- Thousands of anti-Islam and anti-racism protesters clashed in angry rallies around Australia on Saturday.

The most violent clash was in Melbourne, Australia's second-largest city, where police struggled to separate 3,000 opposing demonstrators.

The Victoria state ambulance service treated four people, three for minor injuries from assaults in Melbourne, Ambulance Victoria spokesman Paul Bentley said. The fourth was treated for chest pains. None of the injured was taken to a hospital, he said.

Police arrested two men and a woman in the fracas in Melbourne's downtown Federation Square, Victoria Police spokeswoman Belinda Batty said.

Batty said the three were later released. She said all would be charged, but she could not detail those charges.

Reclaim Australia, a community group, organized rallies in 16 cities and towns around Australia against Islamic extremism, the "Islamization" of Australian society, Islamic Sharia law and the Halal-certification of most meats sold in Australia.

The protesters condemned the cost of the certification for a Muslim minority that is less than 3 per cent of the Australian population as a "Halal tax" on the nation.

They were shouted down with anti-racism slogans by left-wing groups including No Room for Racism, Socialist Alliance and Socialist Alternative.

Reclaim Australia protester Rhonda Cashmore said their protest was not about racism.

"Most here are happy to have immigrants who want to come and fit in," she said. "We're protesting against immigrants who don't want to follow our laws."

Rival protester Gerard Morel said he opposed the anti-Islam rally because his grandfather had been victimized by Nazis during World War II.

"What I see is two groups with diametrically opposing ideas," he said. "They're extreme views that are inconsistent with what Australia stands for."