A march meant to defy Oakland Mayor Libby Schaaf’s crackdown on unpermitted night street protests was extremely slow in developing Friday, when about 60 people gathered at a bustling intersection with no set plan.

A march started about 90 minutes after the protesters gathered, and police cleared the street of the few remaining demonstrators shortly before 11 p.m.

The well-publicized demonstration began at 8 p.m. at 23rd Street and Telegraph Avenue, in the middle of the city’s First Friday Art Murmur festival. By 9 p.m., people were still milling about, and chants decrying the crackdown were drowned out by a nearby calypso band.

At about 9:15 p.m., participants decided they didn’t have the numbers to take on dozens of Oakland police officers who were stationed in the area that night. One protester told the others to get on their social media accounts and urge friends to join them.

The crowd started marching north on Telegraph at about 9:30 but confronted a police line at 27th Street, and decided to reverse course. Another police line blocked them at West Grand Avenue.

Cat Brooks, a community organizer and founder of ONYX/The Anti-Police Terrorism Project, said she came to the march “in solidarity,” though she didn’t put it together.

She said the group that originally called the march, the Black Youth Project, backed out, but that a group with an anti-police stance had convened anyway.

Brooks, who is organizing a separate action next week, said the demonstrators won’t be effective if they work in isolation.

“It’s gonna take the entire community,” she said. “We can’t do this in segments.”

Schaaf began tightening the rules after a May Day march ended in violence, with protesters smashing windows and setting cars ablaze along Auto Row. In the weeks that followed, Schaaf held meetings with merchants from the downtown corridor, and told them she’d devised a strategy to protect their businesses from vandalism.

Oakland police first tested that strategy on May 21, when about 200 demonstrators marched down Broadway after nightfall to decry police violence against African American women. Police shooed them off the street and made them continue their protest on the sidewalk.

Though some activists interpreted the new approach as a curfew and began spreading a #BreaktheCurfew hashtag on Twitter, Schaaf said her office is enforcing laws that are already on the books. “I share their passion,” she said of the protesters. But, she continued, “our intent is to choose a path forward that maximizes everyone’s interests in a balanced way.”

Yet some civil rights attorneys say Schaaf’s approach violates a crowd control policy that stemmed from multiple lawsuits over police use of force to quell protests in Oakland. Attorney Rachel Lederman, who helped write that policy, said it obliges police and city officials to confer with the plaintiffs’ lawyers any time they want to make a change.

Lederman and other lawyers have been meeting with city officials since the May 21 crackdown. “We haven’t been able to work anything out so far,” Lederman said, adding that if the talks reach an impasse, the civil rights lawyers might seek an order from a judge.

Maybe 100 cops lined up the south, another couple dozen staged to the north, #BreakTheCurfew crowd just hanging out. pic.twitter.com/1jwRl4KcMX — Kale Williams (@sfkale) June 6, 2015

Kale Williams, Jenna Lyons and Rachel Swan are San Francisco Chronicle staff writers. E-mail kwilliams@sfchronicle.com, jlyons@sfchronicle.com and rswan@sfchronicle.com. Twitter: @sfkale, @jennajourno, @rachelswan