Farther along the planned route, about 200 Chinese college students mobbed a car carrying two people waving Tibetan flags in front of the city’s Pier 39 tourist destination. The students, who arrived by bus from the University of California, Davis, banged drums and chanted “Go Olympics” in Chinese.

“I’m proud to be Chinese and I’m outraged because there are so many people who are so ignorant they don’t know Tibet is part of China,” Yi Che said. “It was and is and will forever be part of China.”

Only a handful of arrests were made, and no major incidents were reported, police said.

Local officials say they support the diversity of viewpoints, but tightened security following chaotic protests during the torch’s stops in London and Paris and a demonstration Monday in which activists hung banners from the Golden Gate Bridge.

Vans were deployed to haul away arrested protesters, and the Federal Aviation Administration restricted flights over the city. One of the runners who planned to carry the torch dropped out earlier this week because of safety concerns, officials said.

Torchbearers in other cities have complained of aggressive behavior by paramilitary police in blue track suits sent by Beijing to guard the Olympic flame. Although there were no major problems reported in California, they did make their presence felt.

At least one torchbearer decided to show her support for Tibetan independence during her moment in the spotlight. After being passed the Olympic flame, Majora Carter pulled out a small Tibetan flag that she had hidden in her shirt sleeve.

“The Chinese security and cops were on me like white on rice, it was no joke,” said Carter, 41, who runs a nonprofit organization in New York. “They pulled me out of the race, and then San Francisco police officers pushed me back into the crowd on the side of the street.”

Peter Ueberroth, chairman of the United States Olympic Committee, said the U.S. had struck the right balance between preserving freedom of speech for protesters, providing an exhilarating experience for the torchbearers, and preventing a repeat of the chaotic demonstrations that accompanied the torch in London and Paris.

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“As close as anybody can do in a free society, so far it’s looking very good,” Ueberroth said. “Virtually anybody and everybody is being heard.”

On Friday, the IOC’s executive board is to discuss whether to end the remaining international legs of the relay after San Francisco because of widespread protest. The torch is scheduled to travel to Buenos Aires, Argentina, and then to a dozen other countries before arriving in China on May 4. The Olympics begin Aug. 8.

After the San Francisco event, Indonesian officials announced it would significantly shorten its leg of the Olympic torch relay in the capital, Jakarta, citing security concerns. Their relay was scheduled for April 22.

Rogge has refrained from criticizing China, saying he prefers to engage in “silent diplomacy” with the Chinese.

Meanwhile, the White House said anew that President Bush would attend the Olympics, but left open the possibility that he would skip the opening ceremonies. Asked whether Bush would go to that portion of the games, White House press secretary Dana Perino demurred, citing the fluid nature of a foreign trip schedule.

A spokesman for British Prime Minister Gordon Brown said he would not attend the opening ceremony. Brown’s office said the decision was not aimed at sending a message of protest to the Chinese government, that Olympics Minister Tessa Jowell will represent the British government at the opening, and that Brown would attend the closing ceremony.

London is hosting the 2012 Olympics and British officials were expected to attend events throughout the games.

French President Nicolas Sarkozy has said he is debating not attending the opening ceremony as a protest of China’s crackdown in Tibet.