PORTLAND, Oregon (Reuters) - Hundreds of anti-Wall Street demonstrators must leave their protest campsites in Portland, Oregon, by early Sunday morning, the city's mayor said on Thursday, setting the stage for a possible standoff.

City officials said they imposed the 12:01 a.m. Sunday deadline for Occupy Portland protesters to leave two downtown parks because sanitation and safety had deteriorated during six weeks of demonstrations.

"Crime, especially reported assaults, has increased in the area around the camps," Portland Mayor Sam Adams said at a news conference, joining the ranks of U.S. municipal leaders who have run out of patience with such encampments.

Adams, who also cited health and sanitation issues and "two very serious drug overdoses" as an impetus for his decision, said the Occupy movement in Oregon's largest city "has lost control of the camps it created."

He declined to discuss specific plans for removing the estimated 500 to 800 protesters, but said officials would be prepared for "any reasonable eventuality."

Clashes with police have erupted in other cities where officials have tried to remove protest camps, notably in Oakland, California, where a protester was seriously injured, some businesses vandalized and the port briefly closed.

A man was shot to death in Oakland late on Thursday near a downtown plaza where hundreds of anti-Wall Street activists have camped out for a month, stoking renewed calls by some city officials to evict the protesters.

But spokesmen for the so-called Occupy Oakland demonstrators were quick to deny that the shooting, which occurred at a public transit station at the edge of the plaza, had anything to do with the protest movement.

The Oakland police issued a brief statement saying only that officers responding to a report of a shooting adjacent to the plaza "found a victim suffering from a gunshot wound."

The acting police chief, Howard Jordan, later told reporters at an impromptu news conference that investigators were "still trying to put the pieces together," adding, "Obviously, for someone to lose a life, that's a big deal."

Protest organizers said the shooting was an example of gun violence that flares routinely in the city and accused municipal officials of adding to a sense of fear and insecurity by leaving street lights off around the plaza after dark over the past two nights.

Officials in Burlington, Vermont, said on Thursday a 35-year-old man died after apparently shooting himself at a protest encampment in a downtown park in the city. Police said there was no reason to believe the public was at risk after the shooting, but later said they had banned camping at the site over safety concerns.

In South Carolina, protesters drowned out Republican presidential candidate Michele Bachmann during a foreign policy speech aboard the USS Yorktown, a World War Two aircraft carrier. The group of about 30 people accused Bachmann of "dividing Americans."

Police at the University of California, Berkeley, a hotbed of 1960s student activism, said they had released all but two of the 39 people arrested on Wednesday when police prevented a protest camp from taking hold at the campus.

In Tennessee, Republican Governor Bill Haslam will ask prosecutors to drop trespassing citations against anyone arrested last month in Occupy Nashville economic protests, his office said on Thursday.

Also on Thursday, protesters said they would peacefully "occupy" this year's Rose Parade in Pasadena, California.

The iconic Tournament of Roses Parade, which was first held on New Year's Day in 1890, is scheduled for January 2 and broadcast on several U.S. television networks and in dozens of countries around the world.

(Additional reporting by Dan Whitcomb, Tim Ghianni, Harriet McLeod, Zach Howard, Steve Gorman and Noel Randewich; Editing by Paul Simao and Eric Walsh)

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