Protesters associated with Occupy SF, an offshoot of New York's ongoing Occupy Wall Street demonstration, have migrated and formed a thick cluster outside the headquarters of Wells Fargo bank, making it necessary for police officers to escort workers in and out of the building's doors.

Eleven protesters have been arrested at the scene, an officer told San Francisco Chronicle reporter Vivian Ho. They were charged with trespassing.

Protesters also reportedly sat in front of the bank's doors, holding signs that said "make banks pay" and hanging mock eviction signs to the building's doors. The signs were secured by stickers bearing one of the protest's slogans: "We are the 99 percent."

San Francisco Supervisor John Avalos, a mayoral candidate, was in the crowd with the protesters, according to SFAppeal.

"I welcome your fight and I join you in the effort," he said.

SF Weekly reported that the protesters said they wanted to "foreclose the banks."

Activist and author Naomi Klein is also with the protesters at Wells Fargo.

"Occupy Wall Street is not a place — it's a frame of mind," Klein said, according to a woman in the crowd.

People on the scene estimate that the crowd holds about 200 protesters. The demonstrators are obstructing at least three of the four entrances to the bank.

Cable car service to the area has been suspended until the crowd abates, KGO's Kristen Hanes reported.

Creative Commons image via flickr user Steve Rhodes.