Venezuelan President Hugo Chavez and thousands of protesters on Friday vowed to bury a plan to create one of the world's largest free trade zones while Mexico's President Vincente Fox said he and 28 other nations would move forward anyway.
Standing in front of a six-storey banner of revolutionary Ernesto "Che" Guevara in the Argentine resort of Mar Del Plata, Chavez urged a crowd of more than 10,000 anti-American demonstrators to help him block efforts to re-launch talks for a Free Trade Area of the Americas (FTAA).
"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."
But Fox, one of the region's strongest free trade advocates, said a majority of nations participating in the summit were considering forging ahead on an FTAA without the participation of dissenting nations such as Venezuela, Brazil, Argentina, Paraguay and Uruguay.
Top-level negotiators at the fourth Summit of the Americas have so far failed to agree on key language aimed at re-launching talks as soon as April for the proposed bloc stretching from Alaska to Argentina - an ambitious proposal originally raised in 1994 at the first Americas summit in Miami.
The trade zone, if achieved, would rival the European Union as the world's largest, but its creation has been stalled for years amid bickering over US farm subsidies and other obstacles.
The prospect of a rebirth for the FTAA drew hordes of protesters into the streets of the coastal resort Mar del Plata, where leaders shuttled between luxury hotels as security helicopters rattled overhead and armed frogmen guarded the coast in rubber boats that bobbed in a choppy sea.
"Only united can we defeat imperialism and bring our people a better life"
"Bush out! To hell with the FTAA!" the crowds of demonstrators chanted. Some self-proclaimed anarchists spray-painted slogans on a bank, but the crowd was generally peaceful.
Wearing "Stop Bush" T-shirts and unfurling leftist banners on the ocean breeze, protesters said they were also against the US-led war in Iraq and neo-liberalist policies they blamed for Argentina's 2001-2002 economic crisis.
They alternated between soccer chants of "Ole! Ole!" and screams of "Fascist Bush! You are the terrorist!"