LOS ANGELES (CBS) — Occupy LA protesters assembled Friday evening at Pershing Square downtown, creating a peaceful scene in sharp contrast to the rock-throwing, bottle-tossing melee that broke out Thursday night following an ArtWalk event.

The confrontation less than 24 hours earlier resulted in 17 arrests, injuries to at least four LAPD officers and riot police clashing with an estimated 500 protesters.

Police had used rubber bullets and batons in their action to control the crowd. Protesters not only accused the police of using excessive force, they also say police started the whole thing.

Amanda Burden reported for CBS2 and KCAL9 during the melee and Friday.

“I said to the cops, ‘You know why people are throwing things at you? Because no one likes you! Nobody wants you here,’” said Richard Florence of the Occupy LA movement.

The argument Thursday started over protesters writing on sidewalks with pieces of chalk. LA Occupy says they were merely expressing their right to free speech. Police said they were breaking the law.

“It was just supposed to be an art project, writing in chalk on the sidewalk during ArtWalk,” said Stephanie Tatro of Occupy LA. “It was nothing politically motivated.”

“The police overreacted,” said Kandist Mallett, also of Occupy LA. “They escalated a situation and created a riot. It’s really disappointing that peaceful protesters or artists in general are trying to participate in ArtWalk and they’re people getting shot with rubber bullets.”

The city says art or no, people have to follow the law and lawful orders given by police.

“Using chalk to deface public and private property is against the law,” said Chief Charlie Beck. “When police officers tell you to stop doing something, it’s against the law… and you need to stop doing that.”

Mayor Antonio Villaraigosa agreed. “It’s not free speech,” he said. “That’s criminal behavior.”

Occupy LA insists they weren’t the ones who were throwing bottles at police.

“Political oppression is real and police brutality is real,” said Kandist Mallet. “It’s happening here and people really need to participate and inform themselves.”