It was the most turbulent protest since the four-day convention began on Monday. The chaos briefly prevented delegates and members of the media from getting into the Quicken Loans Arena for the evening’s proceedings.

Among those arrested was Gregory “Joey” Johnson, whose torching of the flag at a GOP convention three decades ago led to the landmark 1989 U.S. Supreme Court decision that said flag-burning is speech protected by the First Amendment.

Two officers were assaulted and suffered minor injuries, police said. One officer was seen bleeding from an elbow. Two of those arrested were charged with felonious assault on a police officer, the rest with failure to disperse.

Police Chief Calvin Williams said a protester whose pants caught fire got defensive when a police officer tried to put out the blaze. The man assaulted the officer, and “things escalated from there,” Williams said.

The melee brought to 22 the number of people arrested during the convention, far fewer than some law enforcement authorities had feared.

[fortune-gallery id=”1738061″]

“Right now, I think so far, so good,” Williams said Wednesday night. “We’re still out there, we’re still vigilant, to make sure we finish this day and the last day tomorrow on a positive note.”

The protest took place just outside an entrance to the arena and near a row of popular restaurants where cable news networks had set up for the week.

Carl Dix of the Revolutionary Communist Party said the group organized the burning of the American flag as a “political statement about the crimes of the American empire. There’s nothing great about America.”

Moments after the flag was set on fire, officers charged in to put it out with an extinguishing spray that some in the crowd thought was pepper spray because of similarities in the design of the canisters and the eye irritation caused by the fire-suppression substance.

“You’re on fire! You’re on fire, stupid!” a Cleveland officer shouted at a protester while firing the extinguishing spray.

“Burn that rag! Burn that rag!” supporters of the group yelled.

Pushing and shoving broke out, and police quickly had several group members on the ground in handcuffs. Some in the crowd jeered the officers, yelling, “Blue lives murder!”

About 10 more minutes passed before the crowd was under control.

Earlier in the day Wednesday, blocks away from the arena, a right-wing religious group lifted a banner reading “Jesus is angry with you sinners,” while kissing lesbians mocked their message, helping turn Cleveland’s Public Square into part-carnival, part-debate floor.

The expansive square was a free-flowing mix of ideas and beliefs along with colorful characters pounding on bongos and wailing on a sousaphone.

The day’s demonstrations started when a few dozen people holding banners printed with a red-brick design formed a human wall to mock Donald Trump’s plan to seal off the Mexican border.

“We want to wall off the hate of Trump,” said Tim Chavez, of Columbus.

A half-dozen Trump supporters defended the GOP nominee from attacks by immigration activists.

Police officers used bicycles and their bodies to separate those with opposing views.