The Olympic torch relay descended into chaos in Paris on Monday with officials having to extinguish the flame and carry it by bus when pro-Tibet protesters tried to seize it.
Chinese authorities condemned as "vile" the growing campaign by activists to use the buildup to the Beijing Olympics as a stage on which to condemn China's record in Tibet, on human rights in general and attack its foreign policy.
They said there would be no change to the elaborate ritual of carrying the flame around the world.
The Paris torch relay hit trouble almost as soon as it set off from the Eiffel Tower, and was repeatedly halted by protesters who threatened to break through the imposing security cordon thrown around the athletes carrying the flame.
The torch had to be extinguished at least twice and sheltered in a bus on several occasions from the thousands of demonstrators. A Chinese official was quoted by Xinhua news agency as saying it was put out for safety reasons.
Demonstrators carried banners declaring "Boycott Chinese goods" and "Save Tibet".
"We are doing our best but it will take the world to put pressure on China to help bring democracy and human rights to Tibet," said Phurbu Dolker, a 21-year-old Tibetan refugee.
Police detained 18 protesters, the Interior Ministry said.
Embarrassed Chinese organisers cancelled a reception for the torch at Paris city hall at the last minute after a banner supporting human rights was hung from the facade, Paris mayor Bernard Delanoe told reporters.
"The Chinese officials decided they would not stop here because they were put out by Parisian citizens expressing their support for human rights. It is their responsibility," he said.
It was a second consecutive day of chaos for the torch run.
Thousands of protesters waving Tibetan flags and shouting "Shame on China" turned Sunday's British leg of the international relay billed by Beijing as the "harmonious journey" into an obstacle course. Police detained 35 people.
The torch arrives on Wednesday in San Francisco, where three pro-Tibet activists scaled the cables of the city's famed Golden Gate Bridge and hung protest banners on Monday. "One World, One Dream: Free Tibet," read one of them.
International Olympic Committee (IOC) President Jacques Rogge said he was very concerned "with the international situation and what's happened in Tibet".
"Violence for whatever reason is not compatible with the values of the torch relay and the Olympic Games," he said in a speech to the Association of National Olympic Committees (ANOC) in Beijing. "Some people have played with the idea of boycotts. As I speak today, there is no momentum for a general boycott."
