Six protesters were arrested during a ruckus on a crowded 16th Street Mall on Saturday evening as tourists and dinner-goers walked downtown, some alarmed by seeing a dozen officers in riot gear hanging on the outside of two police vehicles.

Protesters were pepper-sprayed near 16th Street and California, in front of a Jamba Juice, as they tried to stop police efforts to make arrests, said police Sgt. Steve Warneke.

Police on motorcycles were standing guard on various street corners, keeping watch over the crowd of about two dozen protesters banging drums and shouting against organized government. Some protesters wore masks, and some carried signs saying “Free the Prisons” and “Stop Police Brutality.”

“We are protesting police brutality and the mere existence of police in Denver,” said one of the group’s leaders, who did not want his name in the newspaper. “We let cops roam the streets and kill whoever they want with impunity.”

The group, called Anonymous, protests on the fifth day of each month.

Officers in riot gear traveling on two sport utility vehicles stayed a few blocks away from the protesters, trying not to “antagonize them.” Passers-by occasionally stopped to ask officers whether it was safe to keep walking.

No property damage was reported. The arrests were on minor charges, including blocking the street and interfering with police.