MAR DEL PLATA, Argentina - More than 1,000 demonstrators angry about President Bush's policies clashed with police, shattered storefronts, and torched businesses yesterday at the start of the Summit of the Americas as leaders began debating creation of one of the world's largest free-trade zones.
Groups of anti-American protesters turned violent just blocks from the summit. And Hugo Chavez, Venezuela's fiery populist leader, led a peaceful rally against the United States at a soccer stadium filled with at least 25,000 people.
Mr. Chavez is using the meeting to stage a showdown with Mr. Bush and pronounce as dead a free-trade accord supported by Mr. Bush. The accord is called the Free Trade Area of the Americas.
With the two-day gathering of leaders from 34 nations scheduled to end today, negotiators were struggling to find language endorsing the concept of free trade that would satisfy both the United States, its chief booster, and skeptics such as Brazil and Argentina, who complained of U.S. agricultural subsidies.
"Every one of us has brought a shovel, because Mar del Plata is going to be the tomb of FTAA," Mr. Chavez said. "FTAA is dead, and we, the people of the Americas, are the ones who buried it."
Mexican President Vicente Fox said the proposal would move forward anyway because 29 of the nations at the summit were considering cobbling together their own accord - without opponents Venezuela, Brazil, Argentina, Paraguay, and Uruguay.
Thomas Shannon, the new U.S. assistant secretary of state for Western Hemisphere affairs, wasn't aware of Mr. Fox's plan.
"There is significant support within the region for economic integration and for a Free Trade Area of the Americas," he said.
Rioters, separate from the crowd at the stadium, smashed windows, looted stores, chanted anti-Bush slogans, and threw rocks at police. Others lobbed gasoline bombs into a bank, causing a fire that destroyed the interior of the ground floor. Officials said 64 people were arrested but there were no injuries in the protests.
Mr. Bush spent his day away from the turmoil in the streets. Mr. Chavez and Mr. Bush were together in a group session, but Mr. Bush has so far refused to engage Mr. Chavez, and has tried to press the meeting's official themes of creating jobs and promoting democracy.
Mr. Bush met with Argentine President Nestor Kirchner, who has been lukewarm about some aspects of the free-trade agenda. Mr. Bush thanked Mr. Kirchner after the meeting.
"It's not easy to host all these countries. It's particularly not easy to host, perhaps, me," Mr. Bush said.
Police used tear gas in response to the riots and the violence appeared to be under control by evening. Banners carried by the looters and the graffiti they left on walls indicated that they were members of several radical labor unions and far-left political parties that in the past have clashed with Mr. Kirchner.
Before Mr. Bush left on his trip, he brushed off a question about possible protests during a group interview with reporters from Latin American publications.
"Look, I understand not everybody agrees with the decisions I've made, but that's not unique to Central or South America," he said. "Truth of the matter is, there's people who disagree with the decisions I've made all over the world. And I understand that. But that's what happens when you make decisions."
There were also protest marches in Buenos Aires, the capital, where a branch of BankBoston and some fast-food outlets were attacked in the afternoon. Earlier in the day, a major teacher's union had announced a one-day strike to protest Mr. Bush's presence in Argentina.
In Mar Del Plata, the violent protesters first made their way to the steel barriers marking the security perimeter around the meeting site. At first, witnesses said, they threw rocks and gasoline bombs at police manning the checkpoint and chanted slogans attacking Mr. Bush.
Riot police appeared after the attack on the bank and began to fire tear gas and rubber bullets, forcing the protesters to pull back. As they did so, they attacked more than 50 other stores and businesses, shattering windows and piling furniture and papers in the street, where they were set ablaze.
Earlier in the day, Mr. Chavez addressed about 25,000 peaceful protesters for more than two hours in the city's main soccer stadium. Mr. Chavez accused the Pentagon of having a secret plan to invade his oil-rich country, similar to charges, always denied by the United States, that he has made in the past.
"If it occurs to American imperialism, in its desperation, to invade Venezuela, a 100 years' war will begin," he said. Urging Latin American unity in the face of what he called U.S. hegemony, he said that "either our nation will be free or a flag will wave over its ruins. But we will not be a North American colony."
Mr. Chavez's rally was preceded by a long march in a cold rain through the near-empty streets of this resort. Fearing violence and clashes with police, many store owners along the route had closed their businesses and boarded up their windows. That demonstration was peaceful.