OAKLAND, Calif. » The scene was calm but tense early Wednesday as a crowd of hundreds of protesters dwindled to just a few dozen at the site of several clashes between authorities and supporters of the Occupy Wall Street movement a night earlier.

Police in riot gear stood watch only a few yards away from a group of stalwart demonstrators in the aftermath of skirmishes in front of City Hall that resulted in five volleys of tear gas from police, in blasts that seemed to intensify with each round, over a roughly three-hour stretch of evening scuffles.

The conflict began much earlier in the day when police dismantled an encampment of Occupy Wall Street protesters that had dominated a plaza across the street from the government building for more than two weeks.

Police fired tear gas and beanbag rounds, clearing out the makeshift city in less than an hour.

Hours after nightfall Tuesday evening, protesters had gathered at a downtown library and began marching toward City Hall in an attempt to re-establish a presence in the area of the disbanded camp.

They were met by police officers in riot gear. Several small skirmishes broke out and officers cleared the area by firing tear gas.

The scene repeated itself several times just a few blocks away in front of the plaza, where police set up behind metal barricades, preventing protesters from gaining access to the site.

Tensions would build as protesters edged ever closer to the police line and reach a breaking point with a demonstrator hurling a bottle or rock, prompting police to respond with another round of gas.

The chemical haze hung in the air for hours, new blasts clouding the air before the previous fog could dissipate.

The number of protesters diminished with each round of tear gas. Police estimated that there were roughly 1,000 demonstrators at the first clash following the march. About 200 remained after the final conflict around 11:15 PDT, mostly young adults, some riding bicycles, protecting themselves from the noxious fumes with bandanas and scarves wrapped around their faces.

Police have denied reports that they used flash bang canisters to help break up the crowds, saying the loud noises came from large firecrackers thrown at police by protesters.

Helicopters scanned the area late Tuesday and scores of officers wearing helmets and carrying clubs patrolled the streets. Fire crews put out small blazes in trash containers.

Protesters moved about uneasily even as one used a bull horn to express his resolve.

"This movement is more than just the people versus the police," Mario Fernandez said. "It’s about the people trying to have their rights to basic services."

He added, "This crowd isn’t going anywhere anytime soon."

Acting Police Chief Howard Jordan told reporters at a late night news conference that authorities had no other choice, saying the protesters were throwing rocks and bottles at officers.

"We had to deploy gas to stop the crowd," he said, according to a KCBS report.

City officials say that two officers were injured. At least five protesters were arrested and several others injured in the evening clashes.

In the morning raid authorities removed about 170 demonstrators who had been staying in the area overnight after repeatedly being warned that such a camp was illegal and they faced arrest by remaining. City officials said 97 people were arrested.

Protesters promised to reconvene Wednesday morning. Police, meanwhile, remained in riot gear standing watch.

The Oakland site was among numerous camps that have sprung up around the country as protesters rally against what they see as corporate greed and a wide range of other economic issues. The protests have attracted a wide range of people, including college students looking for work and the homeless.

In Oakland, tensions between the city and protesters have been escalating since last week as officials complained about what they described as deteriorating safety, sanitation and health issues at the site of the dismantled camp.

Associated Press reporter Marcus Wohlsen contributed to this report.