Four nudists were cited and detained by police Friday afternoon in front of San Francisco City Hall at a protest against a citywide nudity ban that went into effect today.

At a noon rally on the Polk Street steps, about 10 nude activists faced off against police officers while carrying signs, playing guitar and calling for a recall against Supervisor Scott Wiener, who authored the city ordinance that bans public nudity.

The legislation was approved in a 6-5 vote by the Board of Supervisors in December and includes exceptions for children under the age of 5 and for attendees of certain permitted events, such as the Folsom Street Fair and Bay to Breakers.

Just before 12:30 p.m., about a dozen police officers that had been monitoring the event swooped in and took away the four nude protesters, including longtime nude activists Gypsy Taub -- naked save for a brown coat -- and George Davis, who was only wearing a fanny pack and sandals.

The protesters were taken into the back of a paddy wagon in plastic handcuffs. Police spokesman Officer Albie Esparza said this afternoon the four will be released after police determine if any of them have outstanding warrants.

According to the ordinance, violators will be cited and fined $100, with rising penalties for additional offenses.

Protester Trey Allen, also in the buff with "War is obscene not my body" written across his back, welcomed the citations.

"To end the law we need to be cited by the law," he said.

Public nudity supporter Mitch Hightower called the protest and citations a success in the nudists' fight to show nudity as a form of expression and therefore a constitutional right.

"This is not unexpected," he said about the police action.

Hightower is one of the plaintiffs in a lawsuit to block the ban that was rejected Tuesday by U.S. District Judge Edward Chen.

Hightower said the plaintiffs are convening next week with Christina DiEdoardo, the nudists' lawyer, to discuss options including amending a future lawsuit or filing an appeal with the 9th U.S. Circuit Court of Appeals.

Before the protesters were detained, Davis announced his candidacy for District 8 supervisor to replace Wiener, a mostly symbolic announcement as the next election will be held in 2014.

"Six supervisors and the mayor took away one of your freedoms," Davis said to supporters and some passersby who stopped to take photos of the nude scene on the City Hall steps.

Davis said he has run in past years for San Francisco political posts, including mayor in 2007, on "body freedom issues."