Speaking at an 'anti-imperialist' rally in Buenos Aires, Chavez said Bush was no more than a "political corpse".

Bush arrived in the capital of neighbouring Uruguay, Montevideo, as Chavez addressed the crowd of 40,000.

It is as close as the two rivals will come, separated by just 40 miles across the River Plate.

Chavez, dressed in his trademark red shirt, shouted to the crowds: "The little imperial gentleman from the north must be across the river by now. Let's send him a big shout: Gringo go home!

"We need to tell him North America is for North Americans and South America is for South Americans - this is our America."

Before leaving Brazil, where the US president signed a deal aimed at promoting the bio-fuel ethanol as an alternative to petrol, Bush said his trip was aimed at promoting neighbourly relations.

"My trip is to explain as clearly as I can that our nation is generous and compassionate, " Bush said before heading for the second stop in his five-nation tour, Uruguay.

But protests before his arrival in the capital, Montevideo, ended with demonstrators smashing the windows of two McDonald's stores.

In Brazil on Thursday, about 20 were injured as demonstrations against Bush erupted into clashes on the city's main avenue.