While Occupy Oakland protesters hijacked a news conference at Lake Merritt calling for the ouster of their tent city, Mayor Jean Quan chatted with some of the camp denizens in front of City Hall and put out her own statement asking the camp to leave.

The mayor's impromptu visit happened at the same time five council members, business people and faith leaders gathered at the Lake Merritt Band Shell to express their frustration with the camp, the violence and the effect on downtown businesses. They promised to find a way to boot the camp if the mayor will not do it.

But before Council President Larry Reid could finish his remarks, a crowd of Occupy protesters rushed to the scene and drowned out Reid's words with chants of "Mic check!" and "We are the 99 percent of Oakland and the Bay Area!" as well as promises to defend the camp if another eviction occurs.

At one point, the business leaders and council members, who along with Reid included Libby Schaaf, Desley Brooks, Patricia Kernighan and Ignacio De La Fuente, shouted back: "Occupy Oakland must go!"

Before the disruption Reid said that all the progress the city has made to revitalize its downtown is being threatened by the encampment, which he said continues to be hostile to city officials and a threat to public safety. He said the violence that scarred downtown Oakland after last week's general strike cost more than $1 million and drained scarce resources that should be spent throughout the city. Oakland's image, he said, is taking a hit.

"I am witnessing a city where we will not be able to attract downtown retailers," Reid said. "This city has taken 10 steps backward."

Debra Grabelle works at the camp medical tent and said she's worried that the demand to end the camp would "bring violence into our community."

"I think it's wrong what they are doing. ... Ignacio De La Fuente is my representative. I want him to help support the movement, not undermine it," she said.

The elected officials, Oakland chamber representatives and business groups called for the immediate removal of the camp and said they support "peaceful demonstrations but not camping or rioting." They urged people to shop, eat and buy locally to support businesses that are suffering.

"This is a city of 99-percenters," Reid said forcefully.

For her part, Quan said she chatted with some homeless people at the camp and told them they would have to relocate to the winter shelter opening at the Army Base next week. She said others aired grievances about the lack of jobs and someone she described as an anarchist argued with her about police brutality. She said she assured him that the city was hiring an independent investigator to review all the allegations.

She also said she was pleased that the council majority had come to a consensus over the fate of the camp. After ordering a hands-off approach to the camp for the past two weeks, the mayor issued a statement Wednesday that urges the Occupy Oakland camp to "make a decision to leave immediately."

"Occupation is a tactic, not a solution," Quan said in a prepared statement distributed during the news conference. "Frank Ogawa Plaza cannot sustain permanent living quarters and our economy cannot sustain this occupation.

"I call on elected leaders who are clamoring for an immediate raid to put forward a plan that does not cause additional injury to people, property and our reputation, or result in another re-occupation," Quan said in her statement. "I urge them to join me, the city administrator, police chief and community leaders in implementing a plan to remove the encampment."

How that will happen without a repeat of the violent clashes that followed the Oct. 25 predawn raid on a much smaller camp is a big question.

The encampment that has re-established itself in front of City Hall the past two weeks has grown larger by the day, with more than 180 tents covering the plaza lawn and encroaching into the brick plaza thoroughfare. The camp remains hostile to city enforcement and failed its recent fire inspection, according to the mayor's office. The campers are using hibachis to cook and city officials are worried that people will be hurt if the tents catch fire.

But more than anything else, it is the violence and lawlessness that has turned once supportive elected officials against the encampment.

Brooks spent two nights at the Occupy Oakland camp in its early days and supports the core Occupy mission of protesting against corporate greed. But the councilwoman said the camp has "changed substantially" as it attracts people who are not interested in the core mission and would rather "wreak havoc" on the establishment.

"I don't think it's necessary to continue the camp," Brooks said. "Most of the work takes place during the day."

Contact Cecily Burt at 510-208-6441. Follow her at Twitter.com/csburt.