Anonymous made its first physical denial-of-service attack.

The Bay Area Rapid Transit District police closed at least four San Francisco subway stations following a short, peaceful protest at the Civic Center stop, forcing hordes of commuters to trudge up and down Market Street in search of an open station or an alternate way home, according to CNET news.

Cell service remained accessible this evening. Meanwhile, the U.S. Federal Communications Commission said earlier that it would review BART's shutting off cell service in its stations last week.

The online activist collective Anonymous called for the demonstration at Civic Center station to protest fatal BART police shootings and the subway operator's cutting off of cell service last Thursday afternoon in an attempt to head off a previous protest.

Protesters are angry about the fatal shooting of 45-year-old Charles Blair Hill on July 3 by BART officers in Civic Center station, and the January 1, 2009, fatal shooting of Oscar Grant by BART officers. His shooting--while he was restrained, unarmed, and on the ground--was captured on video from cell phones and cameras and widely distributed on the Internet.

No arrests were made, said Dan Hartwig, deputy chief of police at BART. "We shut down the station because we didn't want to jeopardize the safety of passengers and BART employees," he told reporters.

"I'm not part of any group," said a college student who wanted to be identified only by last name of "Capurro." "I'm just disgusted by the violence we've seen from the BART police."