Hundreds of pro-Tibet protesters have marched in San Francisco, as the city prepares to host the next leg of the international Olympic torch relay.
Demonstrators carrying Tibetan flags marched to the Chinese consulate to denounce Beijing's policy on Tibet.
Officials have promised tight security for Wednesday's torch relay, following chaotic scenes in London and Paris.
Officials in Beijing have condemned the disruption to the procession but promised that it would continue.
Extra police will line the torch's route as it follows a six-mile (10km) route through San Francisco, starting at 1300 (2000 GMT).
Mayor Gavin Newsom said he had been in touch with officials in the UK and France to discuss ways of handling the protesters.
"I'm not naive to the challenge associated with this event," he said.
At a candle-lit vigil on Tuesday near City Hall, South African Archbishop and Nobel Peace Prize laureate Desmond Tutu urged world leaders not to go to 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," he said.
"Tell your counterparts in Beijing you wanted to come but looked at your schedule and realised you have something else to do."
Hollywood actor and long-time Tibet activist Richard Gere attacked China's plans to parade the torch through Tibet.
"The game-plan of bringing this torch to Tibet, as if it was a harmonious society, is so patently false and insulting to the Tibetans," Mr Gere told the rally.
But in San Francisco's Chinatown, community representatives held a news conference to call for a peaceful relay and voice pride over China's hosting of the Games.
"If I support the Olympics, of course I don't support the protests," local resident Ling Li told the Associated Press News agency.
"This is the first time China has had the Olympics. We should be proud of this."
The flame was lit in Greece on 24 March and is being relayed through 20 countries before being carried into the opening ceremony in Beijing on 8 August.
Protests have already caused serious disruption to legs in London and Paris. In Paris, the torch had to be extinguished three times, while in London there were 37 arrests.
The demonstrators are protesting over a security crackdown in Tibet after anti-Chinese unrest.
Tibetan exile groups say Chinese security forces killed dozens of protesters. Beijing says about 19 people were killed in rioting.
OLYMPIC TORCH ROUTE
Torch lit in Olympia on 24 March and taken on five-day relay around Greece to Athens
After handover ceremony, it is taken to Beijing on 31 March to begin a journey of 136,800 km (85,000 miles) around the world
Torch arrives in Macau on 3 May. After three-month relay all around China, it arrives in Beijing for opening ceremony on 8 August