Security was tight in the Argentine capital Buenos Aires tonight as protesters threatened the passage of the Olympic torch through the city.
Police kept small groups of pro- and anti-China protesters apart along the eight-mile (13-km) route.
Chinese guards running in formation around the torch deflected at least one water balloon thrown at the flame from crowds of flag-waving protesters in front of the pink presidential palace.
Activists protesting China's rule of Tibet have pledged peaceful demonstrations but said they would not try to put out the torch during its Buenos Aires relay.
The torch, touring the world ahead of the Olympic Games in Beijing in August, has been a magnet for protests over China policies, in particular its crackdown last month on unrest in Tibet.
In Buenos Aires, Olympic medalist Carlos Espinola, a yachtsman and windsurfer, was the first of 80 people scheduled to carry the torch on the Argentine relay.
After the first stretch through the streets of a riverside neighborhood, torch bearers carried the flame onto a shell and rowed it down the Puerto Madero docks, which are lined with expensive restaurants and bars.
Before the relay started, despite some shouting between pro- and anti-China groups, there were no clashes and police moved quickly to keep the two sides apart.
Buenos Aires had braced for possible violence after intense protests in San Francisco, Paris and London over the past week. Some 1,500 Coast Guard officers, 1,200 police and 3,000 city workers were set to help keep order.
Argentine pro-Tibet activists promised non-violent "surprise actions" during the day, but said they would not try to put out the flame as protesters in London and Paris did.
Beijing, which views the Olympics as an opportunity to showcase its growing emergence on the world stage, has strongly condemned the torch protests, blaming Tibet's spiritual leader, the Dalai Lama, and his followers.
After Argentina, the torch heads to Tanzania, where Kenyan Nobel Peace Laureate Wangari Maathai announced she had pulled out of the relay.
Calls have intensified for world leaders to boycott the opening ceremony of the Olympic Games in August.
Beijing Olympics organizing committee chief Liu Qi said on Friday organizers were working to avoid more chaotic scenes in the remaining legs of the torch relay.