Archbishop Desmond Tutu called for world leaders to skip the Olympic Games in Beijing as Tibet supporters vowed to send their message to China, ahead of the Olympic torch relay in San Francisco Wednesday.

Tutu was among the speakers at a candlelight vigil attended by nearly 2,000 people in downtown San Francisco late Tuesday to protest human rights abuses by China.

"To do anything less than take to the streets of San Francisco would be very un-San Francisco," city board of supervisors member Chris Daly told the vigil.

"The torch will be met with great alarm and significant protest."

In Beijing, International Olympic Committee members said they were determined to go ahead with the protest-marred Olympic torch relay, as they braced for demonstrations in San Francisco.

IOC President Jacques Rogge said protests that disrupted the relay in London and Paris would not cause torch runs to be cancelled.

Tutu lauded the protestors for outpourings of support for human rights and called on US President George W. Bush and the leaders of other nations not to go to Beijing for the Games.

"For God's sake, for the sake of our children, for the sake of their children, for the sake of the beautiful people of Tibet -- don't go," Tutu said in his message to heads of states.

"Tell your counterparts in Beijing you wanted to come but looked at your schedule and realized you have something else to do."

The vigil culminated a day of peaceful, noisy demonstrations that started with a rally at the city's United Nations Plaza and included around 800 protestors marching to the Chinese consulate.

Protesters chanted "Shame on China" and "Free Tibet Now" as they demonstrated outside the consulate buildings."

"This really is an epic moment," actor Richard Gere, chairman of the board of the International Campaign for Tibet (ICT), told the crowd during the vigil.

"The harmonious society (Chinese president) Hu Jintao talks about is a fraud. There can be no harmony without freedom of religion and culture."

San Francisco organizers have already trimmed the route of the torch relay to 9.6 kilometers (six miles), and the course is expected to be altered again at the last minute to stymie protestors.

Pro-Tibet campaigners have shadowed the flame from the moment it was lit in Greece on March 24, as demonstrators accuse China of violating human rights and protest a crackdown in Tibet that they say has left 150 people dead. China says "rioters" killed 20 people.

International leaders are under pressure to boycott the opening ceremony of the Olympics in Beijing on August 8.

Although Bush has consistently said he plans to attend, arguing that the Olympics is about sport not politics, the White House has not ruled out the possibility of Bush missing the event.

In San Francisco, meanwhile, rights campaigners called for calm, urging protesters not to attempt to disrupt the relay and warning that a repeat of the scenes in Paris could backfire.

"We are calling on all of our supporters to remain calm, not to disrupt the torch relay as much as to come out in great numbers and show the strength of the movement," ICT president John Ackerly said.

"There is certainly a danger if people jump in front of it and try to grab the torch, but such actions could sway public opinion against us. We stand by non-violence."

Lucie Morillon, of press watchdog Reporters Without Borders, said a repeat of the scenes in London and Paris could hand China a propaganda victory.

"We want demonstrators to show restraint," Morillon said. "Violence against the torch could backfire and give ammunition for Chinese propaganda."

Some groups have hinted they may attempt to obstruct the torch route in San Francisco. Nyunt Than, president of the Burmese American Democratic Alliance, said his organization was planning "direct action" during the relay.

"That means civil disobedience. It's still considered non-violent. We might be sitting across the street but that is not violent," he said.

Chinese officials have reacted strongly to the idea of stifling their effort to stage the most ambitious Olympic torch relay ever -- 19 countries plus China over a 137,000 kilometer (85,000 mile) journey.

"The disruption and sabotage of the torch relay is a challenge to the spirit of the Olympic charter, the world laws, and peace-loving people around the world," Foreign Ministry spokeswoman Jiang Yu said.

After San Francisco, the torch heads to Buenos Aires and 12 more countries before arriving in China in early May.