DENVER (AP) -- The mayor's spokesman says police were justified in using tear gas and riot gear to break up a crowd of post-Super Bowl revelers "hell-bent on causing trouble."

At least 20 people were arrested and dozens were treated for tear gas exposure in the aftermath of the violence in downtown Denver on Sunday. Property damage was estimated at $160,000.Andrew Hudson, a spokesman for Mayor Wellington Webb, said the crowd was smaller than in the previous year, but was more aggressive. They tipped over trash cans and cars, broke windows and set bonfires.

"I think it could have been a lot worse," Hudson said Monday. "I think if police had not done as well in organizing their efforts, a lot more people would have gotten hurt."

"Clearly, this was a crowd that had no respect for other people's property. They were hell-bent on causing trouble," he said.

Denver was one of several cities statewide that reported problems with rowdy fans after the Denver Broncos defeated the Atlanta Falcons in Miami to win their second consecutive NFL title.

From Coors Field to the Capitol, pockets of fans tipped over trash cans and cars, broke windows in dozens of buildings, spilled newspaper boxes, ripped down street signs and lit bonfires.

Police used tear gas, horseback patrols and other riot-prevention measures to break them up. Officers in full riot gear banged nightsticks on shields and walked side by side through the streets to force the crowds to disperse.

"It was rowdy and the police acted with as much restraint as they could," Hudson said. "They also effectively used tear gas where it got really out of control."

In northern Colorado, police officers in Greeley also used tear gas to disperse crowds. Three people were arrested and two hospitalized for minor injuries.

About 50 Fort Collins officers used pepper spray and batons to control a crowd of up to 4,000 revelers, who were mostly students at nearby Colorado State University. One man was arrested.

In Grand Junction, officers tried dogs and tear gas before resorting to water streaming from fire hoses to break up fans tying up traffic by packing a main street. At least five people were arrested.