The body language said it all - George W. Bush seeing the back of Hugo Chavez in the conference hall and walking on.

And the rift between the Venezuelan and American presidents was symptomatic of wider divisions that sank the Americas Summit in Mar del Plata.

Reducing poverty was top of the agenda, but the talks were overshadowed by a row over reviving the idea of a free trade area stretching from Alaska to Argentina.

It is a pet project of George W Bush, but is strongly opposed by a group of countries known as Mercosur, which includes Brasil and Argentina.

The plan has aroused particularly intense passions in Argentina, where many hold policies backed by Washington responsible for the economic meltdown of 2001.

Staunch US alllies such as Mexico tried to press forward with the free trade agenda at the summit, but the sceptics were unmoved.

Diplomatic decorum was maintained, but on the streets of Argentine cities protestors made it abundantly clear just how hard a sell free trade is in this part of the world.

Dozens of people have been arrested in anti-summit riots.

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US President George W. Bush arrived in Brazil after failing to win a date for future talks on free trade at an Americas summit marked by fierce anti-US protests. (AFP)