By Laird Harrison

SAN FRANCISCO (Reuters) - Anti-Wall Street activists in San Francisco, who hold one of the largest remaining Occupy camps on the West Coast, essentially rejected an offer to trade their compound for a new site even as officials said time was short for a deal.

The offer came as mayors in other major U.S. cities have moved in to dismantle similar encampments that have sprouted over the past two months as part of the Occupy movement against economic inequality and excesses of the U.S. financial system.

But the rejection late on Tuesday appeared to harden lines between the city and protesters, with a city negotiator saying officials wanted tents gone from the current site by noon on Thursday but stopping short of issuing an ultimatum.

"I'm willing to come back and continue this exchange," said Mohammed Nuru, deputy director for operations, at an impromptu Wednesday meeting at the Financial District site. "But time is short. We do not want tents on this site as of noon tomorrow."

He said dialogue with the protesters would continue, declining to say what would happen if they did not soon clear out. The city had previously indicated simply that the protesters could not stay indefinitely.

The apparent escalation came hours after police in Los Angeles raided an Occupy camp in that city, pulling down tents and arresting nearly 300 people. Meanwhile the threat of a raid in Philadelphia prompted protesters to quit a camp there.

While the evictions in Los Angeles and Philadelphia avoided violence, not all have been peaceful. A similar attempt to clear a camp last month in Oakland evolved into one of the most violent episodes since the anti-Wall Street movement began.

Across the bay in San Francisco, some Occupy members appeared determined to take a stand in Justin Herman Plaza, a camp within view of major bank branches and upscale restaurants where the first tents went up two months ago.

"We know we are not welcome here and that's why we want to stay," said James Morry, a member of the group's Outreach Working Group.

TOTAL CONSENSUS

The occupiers did not vote on the mayor's proposal but simply recognized that many people at its general assembly meeting were opposed, said Kames Geraghty, who staffed the camp's media tent on Wednesday. The group's General Assembly requires total consensus to reach a decision.

Some people in the group wanted to flatly reject the proposal. Others wanted clarification and some wanted to negotiate further, he said. The group planned further discussion on Wednesday.

"Occupy San Francisco doesn't exist," Geraghty said, explaining the difficulties of reaching consensus in such a diffuse group. "It's only an idea in people's heads."

The mayor's office did not respond to requests for comment on Wednesday. Christine Falvey, a spokeswoman for the mayor, had said Tuesday that the new site on offer -- a former school -- offered advantages over the current camp.

"It's larger than the site they are in now," she said. "There is running water and restroom facilities, which is key to our health and safety concerns."

The proposed license agreement for the site at 1950 Mission Street prohibits cooking, children and pets, which could be deal-breakers, said Morry, the Occupy outreach member.

"Even though there are no children here now, we cannot in good conscience accept a contract that says we cannot address the impact of the crisis on the most vulnerable members of society, our children," he said.

The city negotiator, Nuru, later said San Francisco would consider protesters' concerns about limits on pets, children, cooking and privacy at the new site.

At the current site on Wednesday, portable toilets provided by labor unions were overflowing. In addition to sanitation problems, the current camp was preventing other people from using the park, which includes bocce ball courts.

Occupier Chance Martin said the campers had worked to comply with city health and safety requirements, saying campers had cleared tents from the bocce ball courts and that bocce players were using them.

(Editing by Cynthia Johnston and Dan Whitcomb)