The San Francisco Police Department violently raided a San Francisco benefit party for student activists last night after a fire marshal shut down the crowded event.

Police arrested 11 people. A 23-year-old man remains jailed on felony aggravated assault charges, but the others have been released, said police spokesman Officer Samson Chan. While in custody, one of the people arrested was struck in the face by a Sheriff's deputy while sitting quietly and not resisting, according to a party-goer who was recently released from jail.

Around 1 a.m. a UC Berkeley student who had stepped out of the party near the corner of Mission and Seventh Street saw a police officer try to get inside. The student said that when people shut the door and refused to let the officer in, he told them he would call the fire marshal and tear down the door. Within a few minutes the fire marshal showed up, and the organizers allowed him inside after briefly considering the situation.

But Officer Chan said that it was the fire marshal who showed up first, and that the marshal was there because several neighboring residents and businesses had called 911 to complain. Chan claims that when the police showed up, the crowd "threw bottles and explosives" at the officers, prompting them to request emergency backup.

People at the party said they heard what sounded like two m-80 explosions during the night but did not see anyone trying to throw anything at the officers.

According to one account, there were at least two undercover officers already inside the party when the fire marshal showed up. He said the undercover officers started arresting people and "held them up against the wall by their necks," when the fire marshal entered the party. The part-goer told Indybay that when the people streamed out of the party they found cops outside, with more officers continuing to arrive.

"There was no mention of any undercover officers," said Chan, after reviewing the police's report. He said that the SFPD do use undercover officers, but doesn't see why they would have been at the party.

One of those arrested told Indybay that he was tazed after police threw him to the ground and handcuffed him. But when he spoke to arresting officers about the incident, he was told that the San Francisco's police officers don't carry Tazers. The officer confirmed to him that he had been tazed and suggested a civilian must have tazed him while the police were arresting him, he said.

Chan confirmed that the department doesn't use tazers. He said he doesn't have any information to indicate another police agency was involved in the incident, but it is still early in the investigation and that more information be available later in the week.