BUENOS AIRES, Argentina — Argentine runners carried the Olympic torch past fenced-off protesters today, as hundreds of China supporters in red windbreakers tried to reverse weeks of bad publicity for the host of the Summer Games.

Activists opposing China's human rights record unfurled banners and promised "entertaining surprises" but pledged to keep their demonstrations peaceful after protests disrupted stops in London, Paris and San Francisco. At least three water balloons were thrown at the flame at it passed the presidential palace, but guards batted them away.

Hundreds of spectators cheered as Chinese delegates wearing Argentina's blue-and-white lit the torch from a lantern that has carried the flame from the site of the ancient Olympic games in Greece.

Mayor Mauricio Macri held the slender aluminum torch aloft, then passed it to three-time Olympic windsurfing medalist Carlos Espinola, who jogged into Buenos Aires streets flanked by Chinese bodyguards. Heavyset police from Argentina's navy huffed to keep up.

Rowers sped the flame down a muddy River Plate canal, their long oars flashing beneath gathering storm clouds, before runners on land jogged it past the pink presidential palace. Winds caused the propane-powered torch to flicker, but it didn't go out.

A sea of about 500 China supporters in red windbreakers handed out by organizers waved banners and denounced what they called political interference in the ceremony.

"We are here to celebrate the Olympics," said Shao Long Chen, a 19-year-old Chinese immigrant. "It's a great source of pride for us that the Olympics are being held in Beijing and that the torch is passing through Buenos Aires."

As for the protesters nearby, he said: "They're using sports to deliver a political message, and that's not right."

Protesters say China doesn't deserve to host the Olympics because of its human rights record, its harsh rule in Tibet and its friendly ties with Sudan.

About 25 Falun Gong supporters lit a "human rights torch" and marched along the route to protest China's ban on the spiritual movement. But Liwei Fu said the protest would remain peaceful: "We do not want confrontations."

Other demonstrators held up "Free Tibet" banners, and pro-Tibet activists promised unspecified actions.

"There will be very entertaining surprises all along the route," said Jorge Carcavallo, passing out "Free Tibet" leaflets.

Liu Qi, head of the Beijing organizing committee, told senior International Olympics Committee officials in Beijing on Friday that additional steps had been taken to protect the flame, "and we're very confident and comfortable with that," IOC spokeswoman Giselle Davies said.

Argentine officials were bent on avoiding the kind of trouble that disrupted earlier torch stops in Paris, London and San Francisco. They placed about 1,300 federal police, 1,500 naval police and 3,000 traffic police and volunteers along the 8½-mile (14-kilometer) relay route.

The goal, said sports official Francisco Irarrazabal, was to ensure security "without going to the extreme that nobody will be able to see the torch."

Organizers canceled a planned photo opportunity Thursday as the flame arrived from San Francisco, and Chinese guards protected it overnight. Argentine officials wouldn't say where; "That's a state secret," Irarrazabal quipped.

Friday's ceremony began with a tango performance along a canal. The route passed by the pink Government House and the iconic Obelisk, a traditional protest spot, and was ending at an equestrian club with Argentine tennis great Gabriela Sabatini as the last runner.

Following the relay, the torch will be tucked aboard a Chinese jetliner and flown to Tanzania.

Many Argentines didn't want any of the controversy. Ana Maria Tassano, who runs a chic leather goods store, said people should simply be celebrating the Olympic torch.

"We have too many other problems to be worrying about the torch," she said.