Authorities detained activists, increased the number of police on the streets, disconnected some cell phone text messaging services and censored Internet postings about the call to stage protests in Beijing, Shanghai and 11 other major cities.

Police took at least three people away in Beijing, one of whom tried to place white jasmine flowers on a planter while hundreds of people milled about the protest gathering spot, outside a McDonald's on the capital's busiest shopping street. In Shanghai, police led away three people near the planned protest spot after they scuffled in an apparent bid to grab the attention of passers-by.

Many activists said they didn't know who was behind the campaign and weren't sure what to make of the call to protest, which first circulated Saturday on the U.S.-based Chinese-language news website Boxun.com.

The unsigned notice called for a "Jasmine Revolution" -- the name given to the Tunisian protest movement -- and urged people "to take responsibility for the future." Participants were urged to shout, "We want food, we want work, we want housing, we want fairness" -- a slogan that highlights common complaints among Chinese.

The call is likely to fuel anxiety in China's authoritarian government, which is ever alert for domestic discontent and has appeared unnerved by protests in Egypt, Tunisia, Bahrain, Yemen, Algeria and Libya. It has limited media reports about them, stressing the instability caused by the protests, and restricted Internet searches to keep Chinese uninformed about Middle Easterners' grievances against their autocratic rulers.

Though there are many similarities between the complaints voiced by Middle East citizens and the everyday troubles of Chinese, Beijing's tight grip on the country's media, Internet and other communication forums poses difficulties for anyone trying to organize mass demonstrations.

Extensive Internet filtering and monitoring meant that most Chinese were unlikely to know about the call to protest Sunday. Boxun.com is blocked, as are Twitter and Facebook, which were instrumental in Egypt's protest movement. Tech-savvy Chinese can circumvent controls, but few of the country's Internet users seek out politically subversive content.

Anti-government gatherings in China are routinely stamped out by its pervasive security forces, which are well-funded and well-equipped. A pro-democracy movement in 1989 that directly challenged the Communist government was crushed by the military and hundreds, perhaps thousands, were killed.

On Saturday, President Hu Jintao ordered national and provincial officials to "solve prominent problems which might harm the harmony and stability of the society."

One person sitting in the McDonald's after the brief protest in Beijing said he saw Sunday's gathering as a dry run.

"Lots of people in here are Twitter users and came to watch like me," said 42-year-old Hu Di. "Actually this didn't have much organization, but it's a chance to meet each other. It's like preparing for the future."

With foot traffic always heavy at the Wangfujing pedestrian mall, it was difficult to discern who showed up to protest, who came to watch and who was out shopping. Many wondered if there was a celebrity in the area because of the heavy police presence and dozens of foreign reporters and news cameras.