Nine people were arrested and at least two people injured in Oakland, California on Monday, during the third night of demonstrations criticizing the acquittal of Florida neighborhood watch captain George Zimmerman, Bay Area News Group reported.

One of the victims, a waiter at a local restaurant, was reportedly attacked with a hammer while trying to stop people from smashing the business' windows.

"Protesters with black masks approached the window and tried to bang at it," a co-worker, Phillip Ricafort, told Bay Area Media Group. "(The waiter) said, 'Don't do that!' and the guy turned around and smacked him in the face with a hammer."

The other victim, a demonstrator, was injured after allegedly being hit in the shoulder by a police projectile.

KNTV-TV reported that demonstration began Monday evening, when about 250 protesters -- many carrying signs bearing the image of 17-year-old Trayvon Martin, who Zimmerman shot and killed in February 2012 -- gathered at Frank Ogawa Plaza and briefly made their way onto Interstate 880 before marching through the city, as local police brought in both officers from neighboring departments and the California Highway Patrol to assist in handling arrests.

"We recognize the death of Trayvon Martin as a tragic event felt throughout the community," Mayor Jean Quan said in a joint statement with interim Police Chief Sean Whent and City Administrator Deanna Santana. "We understand the verdict announcement is an emotional one. We are committed to supporting peaceful assembly and freedom of speech."

Media outlets also reported being attacked during the evening. KPIX-TV reporter Christin Ayers also said on Twitter that vandals broke into one of the station's live trucks, breaking a window and stealing a photographer's wallet. In Los Angeles, KCAL-TV reporter Dave Bryan and a photographer were tackled by two people while Bryan was covering protests there.

Watch KNTV's report on the protest, aired Monday, below.

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