OAKLAND, Calif (Reuters) - Oakland Mayor Jean Quan, who was booed out of a public square by protesters against economic inequality on Thursday, apologized for a clash between police and demonstrators that badly injured an ex-Marine.

Quan, who has drawn withering criticism for her handling of a confrontation with so-called "Occupy Wall Street" protesters, said in a written statement that she had met with ex-Marine Scott Olsen and his parents and was concerned about his recovery.

Olsen, 24, was struck in the head during protests in Oakland on Tuesday night and has become a rallying cry for the protests nationwide.

A spokesman for Highland General Hospital in Oakland said Olsen remained in fair condition on Friday, upgraded from critical one day earlier, and was visiting with his parents.

"I am deeply saddened about the outcome on Tuesday," Quan said in the statement, which she also delivered from her office in a videotaped posted online. Shouts of protesters rallying outside City Hall can be heard in the background of the video.

"It was not what anyone hoped for. Ultimately, it was my responsibility, and I apologize for what happened," she said, concluding: "We can change America, but we must unite and not divide our city. I hope we can work together."

The disturbances in Oakland have made it one of the hubs of the Occupy Wall Street movement, which began in New York City last month to protest economic disparities, high unemployment and government bailouts of major banks.

Makeshift encampments sprouting up in cities across the country have forced local officials to walk a fine line between allowing peaceful assembly and addressing concerns about trespassing, noise, sanitation and safety.


Quan pledged to work with the Occupy Oakland activists but said "we need to have direct communications between city staff and your representatives."

Quan had paid a visit late Thursday night to a rally and speakers' forum organized by protesters at Frank Ogawa Plaza, a public square adjacent to the mayor's office that has been the fulcrum of demonstrations.

She was greeted with a hail of angry boos and catcalls and hastily retreated with her staff back to City Hall, followed by protesters shouting, "Get out, go home!" and "Resign!"

In her videotaped statement, Quan said she was "asking" protesters to refrain from camping overnight in the plaza.

Police forcibly dismantled the encampment on Tuesday, and protesters were marching to retake it when Olsen was critically injured in the confrontation with police.

Protest organizers said the ex-Marine was struck in the head with a tear gas canister fired by police. City and police officials have not said how they believe Olsen was hurt but police opened an investigation into the incident.

Protesters reclaimed the plaza on Wednesday night and police kept their distance.

On Friday, hundreds of protesters returned again to the square for a rally attended by documentary filmmaker and liberal activist Michael Moore, who was loudly cheered as he addressed the crowd.

"We've seen the militarization of our local police departments because Congress has spent billions to buy them armaments ... even spying systems to prepare them for what they believe is the inevitable," Moore said. "Sooner or later the people aren't going to take it anymore."

Organizers have called for a general strike in Oakland one day next week over what they called the "brutal and vicious" treatment of protesters there.

(Writing by Dan Whitcomb and Steve Gorman; Editing by Greg McCune)

Mochila insert follows.

[Image from Gavin Newsome's Flickr stream.]