More than 1,000 demonstrators angry about President Bush's policies clashed with police, shattered storefronts and torched businesses Friday, marring the inauguration of the Summit of the Americas (search) as leaders began debating creation of one of the world's largest free trade zones.

The chaos reflected the often violent, worldwide debate on free trade (search) as the United States and Mexico pushed to relaunch talks on a zone stretching from Canada to Chile. Past summits on the issue — including last year's gathering of Asian-Pacific leaders in Chile — have drawn bitter opposition and similarly angry protests.

As leaders inaugurated the two-day summit to work out their differences on free trade, a group of protesters threatened a barricade of riot police, prompting authorities to fire tear gas into the crowd.

The protesters, armed with large wooden clubs, began smashing storefront windows and setting at least one bank on fire just outside the gated summit security zone. One restaurant with anti-Bush posters plastered across its windows was untouched.

Car sirens wailed and residents — including elderly people and children — fled as protesters launched rocks with slingshots and threw sharpened sticks at police. They also set fire to U.S. flags, using them as fuel for bonfires.

Officials said 64 people were arrested but there were no injuries in the protests.

Ramon Madrid, a hotel manager, hurriedly closed up.

"I don't like Bush, but this is too much. There is no need for violence," Madrid said.

Anti-American protests also turned violent elsewhere as demonstrators attacked U.S. interests in other Argentine cities. Four police officers were injured in Rosario in clashes that followed an attack on a branch of U.S.-based Citibank.

In neighboring Uruguay (search), hooded protesters chanting anti-Bush slogans attacked a series of bank buildings, shops and shattered windows in an outburst swiftly quelled by riot police. Leftist groups were blamed.

Venezuelan President Hugo Chavez (search) emerged as the most strident opponent of the plan, addressing a separate crowd of more than 10,000 peaceful protesters hours before the summit convened in this normally tranquil seaside resort.

Chavez vowed to defeat the Free Trade Area of the Americas, or FTAA, once and for all. Speaking before a six-story banner of revolutionary Che Guevara (search), Chavez urged the throng — including soccer great Diego Maradona and Bolivian presidential hopeful Evo Morales — to help him fight free trade.

"Only united can we defeat imperialism and bring our people a better life," he said, adding: "Here, in Mar del Plata, FTAA will be buried!"

Before Chavez's speech, demonstrators flooded the streets, shouting "Get out Bush!" and "Fascist Bush! You are the terrorist!"

Mexican President Vicente Fox (search) said the FTAA proposal would move forward anyway because 29 of the 34 nations taking part in the summit were considering cobbling together their own FTAA — without opponents Venezuela, Brazil, Argentina, Paraguay and Uruguay.

Thomas Shannon, the new U.S. assistant secretary of state for Western Hemisphere affairs, said he wasn't aware of Fox's plan, but that "there is significant support within the region for economic integration and for a Free Trade Area of the Americas."

Argentine President Nestor Kirchner (search) was critical of the United States during the summit, saying Latin America will no longer tolerate American meddling. Kirchner said past American policy "not only generated misery and poverty but also a great social tragedy that added to institutional instability in the region, provoking the fall of democratically elected governments."

Top-level negotiators at the summit have so far failed to agree on key language aimed at relaunching talks as soon as April for the proposed FTAA — an ambitious proposal originally raised in 1994 at the first Americas summit in Miami.

The trade zone would rival the European Union as the world's largest, but its creation has been stalled for years amid bickering over U.S. farm subsidies and other obstacles.

Chavez and protesters argue that free trade is being forced on Latin American countries. He has instead pushed for an anti-FTAA deal based on socialist ideals. He has used Venezuela's oil wealth to push for regional solidarity, offering fuel with preferential financing to various Caribbean and Latin American countries.

Venezuela is a member of the Organization of Petroleum Exporting Countries (search) and is the world's fifth largest oil exporter as well as a major supplier to the U.S. market.

Chavez also regularly claims the United States is trying to overthrow his government, something the U.S. denies.

Joking about his rivalry with Bush, the Venezuelan president has said he might try to sneak up and scare the U.S. president during the summit.

When asked how he would react to a close encounter with Chavez, Bush said he would be polite.

"That's what the American people expect their president to do, is to be a polite person," he said. "And if I run across him, I will do just that."

After meeting with Bush, Kirchner made no mention of free trade but said the two had a frank talk about Argentina's struggle to extricate itself from its financial meltdown.

Kirchner led a difficult renegotiation of more than $100 billion in public debt that was the largest sovereign default in history.

"The president was quite frank," Bush said.

Some 40 percent of Argentina's 36 million people remain in poverty, and many blame trade liberalization for destroying local industries and causing a flood of cheap imports.