Three Occupy Denver protesters were arrested and two officers were injured during clashes in Civic Center Park on Sunday afternoon.A state trooper was injured when he was hit with an object in the head and a police officer twisted his knee, Denver police spokesman Sonny Jackson said. Both officers were taken to a hospital for evaluation.Jackson blamed the conflict on a small group of agitators in a crowd of about 100 people."This is an isolated group of these individuals who seem to want to be aggressive, and they want to act in an agitated fashion," Jackson said."It's getting to be more and more of a dangerous situation," he said.After a flurry of tense afternoon scuffles between protesters and police ended with a few arrests, many people left the park after dark.The conflict happened after police arrested 17 Occupy Denver protesters on Saturday night as officers in riot gear cleared tables, chairs and tents, that police said were illegally blocking the sidewalk. Police said those arrested were interfering with officers removing the encampment gear.Occupy Denver issued a statement Sunday blaming the Saturday night clashes on police aggression, saying, "Officers assaulted demonstrators who were just standing on the sidelines." The statement said a protester was hospitalized after being struck by an officer's motorcycle, and other protestors were hit with pepper-spray balls fired by police."All of this dangerous mayhem, completely instigated by police under the orders of our Mayor (Michael Hancock), was directed at peaceful protesters," the protesters statement said.The trouble on Sunday started about 4:40 p.m. after a dozen uniformed police -- none in riot gear -- removed a folding table that activists were using to served food on a sidewalk. There was no conflict when the table was hauled away, but some officers were holding mace spray bottles.No one claimed the table, so police placed it in a patrol car.But when a female officer tried to drive away, a male protestor stood in front of the patrol car, ignoring requests to move, Jackson said.Jackson said the man blocking the patrol car incited others to join in."They got in front of her car and started rocking her car back and forth like they were going to tip her car over," Jackson said. "She called for help."Other officers arrived and tried to move the crowd back."Unfortunately, the crowd became more aggressive, started coming at the officers," Jackson said, and officers sprayed mace to force people back. The man who blocked the car was arrested on a charge of interfering with police, Jackson said. A woman was arrested after she pushed an officer, Jackson said. And a man was arrested when he tried to interfere with the woman being arrested. Since Wednesday, police began handing out written notices ordering people to remove personal items illegally obstructing the sidewalk and other public "right of ways." The flyers said those who failed to remove belongings could face up to one year in jail and a $999 fine.Police have warned protesters they will enforce the law and make arrests if people continue to obstruct sidewalks with tents and other gear.Occupy Denver activists said they were being punished for legally sleeping on the sidewalk without tents and their free speech rights were violated.Protestors vowed to not be driven from the park."We are not going anywhere," the Occupy Denver statement concluded.