A Ku Klux Klan rally Saturday set off a scuffle between rock-throwing anti-Klan protesters and police, who fired tear gas into the crowd and arrested about 20 people.

No serious injuries were reported, but ambulances picked up several people overcome by gas. Police hustled away the 50 Klansmen, who were unharmed.

Witnesses said the trouble began when a young white man wearing a Confederate-flag T-shirt walked into a mostly black crowd of 500 to 600 protesters packed behind police lines.

Pushing and shoving ensued and police moved in to break it up. The tear gas soon followed.

“There was this big fight in the middle of the crowd (that police) were trying to stop,” said witness Chris Hadley. He said many in the crowd were unaware of the fight and thought the police action was unprovoked.

Police fired numerous volleys of tear gas over a 45-minute span and used a large spray gun spewing pepper gas.

The protesters broke up and reformed several times into smaller groups, occasionally throwing tear gas canisters back at police and hurling rocks and bottles.

The Klansmen, led by Jeff Berry, Imperial Wizard of the American Knights of the Ku Klux Klan, railed against interracial marriage, homosexuality and the national holiday Monday honoring Martin Luther King Jr.