Argentina readied thousands of police to guard the Olympic torch on the next stop of its world tour as calls grew for world leaders to boycott the Games’ opening ceremony over China’s human rights record.

Some Argentine activists opposed to China’s rule of Tibet have vowed “surprise actions” when the torch is carried through Buenos Aires tomorrow but they swore off violence.

“I want to announce that we are not going to put out the torch,” said Jorge Carcavallo, the head of an Argentine pro-Tibet group. “But we are going to make surprise and peaceful protests across the city.”

Rival demonstrations by human rights activists and pro-Chinese supporters forced officials to abruptly change the torch’s route through San Francisco yesterday.The torch’s international relay have also sparked chaotic demonstrations during stops in London and Paris, where protests over China’s crackdown on Tibet forced organizers to put it out twice.