Beck Diefenbach / AP
Occupy Oakland protestors burn an American flag found inside Oakland City Hall on Saturday.
Story updated 12:30 p.m. ET:
Oakland officials on Sunday were inspecting damage inside City Hall that was caused by about 50 Occupy protesters who broke in and smashed glass display cases, spray-painted graffiti, and burned the U.S. and California flags.
The break-in on Saturday was the culmination of a day of clashes between protesters and police. At least 300 people were arrested on charges ranging from vandalism and failure to disperse.
At least three officers and one protester were injured.
Mayor Jean Quan said Occupy protesters have caused an estimated $2 million in damages from vandalism since October. She said the cost to the city related to the Occupy Oakland protests is pegged at about $5 million.
Riot police fought running skirmishes with anti-Wall street protesters in Oakland. TODAY's Thomas Roberts reports.
The scene around City Hall was mostly quiet Sunday morning. It was unclear whether protesters would mount another large-scale demonstration later in the day.
Story updated 6:00 a.m. ET:
A U.S. flag was burned by a group of protestors inside City Hall, according to City Council President Larry Reid. City officials also said three police officers and one protester were injured during Saturday's events.
Story updated 3:15 a.m. ET:
Sgt. Christopher Bolton of the Oakland Police Department told msnbc.com that the number arrested was likely between 200 and 300. "We are still processing the arrests," he said. He was speaking after the release of a statement on the Oakland City website that put the number of arrests at 200. "That figure is probably on the low side and we don't have a confirmed total yet," said. Sgt Bolton. In the statement, released in a PDF file format, Oakland Mayor Jean Quan said: "Once again, a violent splinter group of the Occupy Movement is engaging in violent actions against Oakland. The Bay Area Occupy Movement has got to stop using Oakland as their playground." The statement also said there were reports of damage to exhibits inside City Hall during the protest.
Story published 1:30 a.m.:
Police arrested about 300 people Saturday as Occupy Oakland protesters were thwarted trying to take over a vacant convention center and enter a YMCA. Protesters later broke into City Hall, where they burned a flag taken from inside.
Police used tear gas and "flash" grenades in the afternoon against 2,000 protesters who tried to tear down fences around the vacant Henry Kaiser Convention Center, where they hoped to establish a new camp. Police said some demonstrators started throwing objects at officers. There were at least 19 arrests in the afternoon.
After 6 p.m. (9 p.m. ET), police in riot gear declared a group of protesters gathered near the YMCA under mass arrest for failing to disperse, according to local media reports and livestreams. Police said about 100 demonstrators were arrested at the YMCA.
Several protesters at the YMCA appeared to be put hard to the ground as police moved in and at least one protester had blood on his face.
Protesters chanted, "Let us disperse," but instead were taken one by one for police processing.
Some protesters claimed they were trying to flee police by running through the YMCA rather than take over the building.
Later in the evening, about 100 police officers surrounded City Hall while others swept the inside of the building.
Police arrived after protesters had broken into City Hall, stole an American flag from the council chamber and set it ablaze, the Oakland Tribune reported. Officers stomped out the fire.
Earlier, protesters met at Frank Ogawa Plaza around noon and marched toward the convention center in hopes of making it their new meeting place and social center, NBCBayArea.com reported.
Read NBCBayArea.com coverage of the protest
Oakland officials said about 250 people were in the group when the protest started but the crowd grew to about 2,000.
Earlier during the rally one of the organizers, Shake Anderson, said, "We are here to protect each other and to be civil disobedient. ... We're doing it to change the world, not just today but every day."
Stephen Lam / Reuters
Police officers arrest an Occupy Oakland demonstrator during a clash Saturday in Oakland, Calif., where officers fired tear gas at hundreds of protesters who tried to take over a shuttered convention center.
The protesters were walking through Laney College around 2:30 p.m. Some people were wearing bandanas over their mouths and others were holding signs saying, "We are the 99%." A marching band dressed in pink and black tutus and neon pick tights also was in the crowd.
Officer Jeff Thomason said police started making arrests when some in the crowd started throwing objects at them during the afternoon rally. Three officers were injured, police said, but did not elaborate.
@OaklandPoliceCA tweeted around 3 p.m., "Area of Oakland Museum and Kaiser Center severely impacted. Persons cutting and tearing fences for entry. Bottles and objects thrown at OPD."
Once they reached the center, organizers planned to kick off a two-day "Oakland Rise-up Festival" to celebrate the establishment of the movement's new space.
Occupy Oakland spokesman Leo Ritz-Bar said the action would signal "a new direction for the Occupy movement: putting vacant buildings at the service of the community."
Stephen Lam / Reuters
Occupy Oakland demonstrators shield themselves from an explosion Saturday during a confrontation with the police near the Oakland Museum of California in Oakland, Calif.
He also warned that protesters could retaliate against any repressive police action by blocking the Oakland International Airport, occupying City Hall or shutting down the Port of Oakland.
City officials said that while they are "committed to facilitating peaceful forms of expression and free speech, police would be prepared to arrest those who break the law.
"The city of Oakland will not be bullied by threats of violence or illegal activity," city administrator Deanna Santana said in a statement issued Friday.
This article includes reporting from NBCBayArea.com, The Associated Press and msnbc.com's Miranda Leitsinger and Alastair Jamieson.
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