On the eve of his first official overseas trip since being diagnosed with cancer, Hugo Chávez has launched a blistering attack on Barack Obama, describing the US president as a "clown" and an "embarrassment". "Focus on governing your country, which you've turned into a disaster," the Venezuelan president told state TV on Monday. Chávez touched down in the Uruguayan capital, Montevideo, on Tuesday for a summit of Mercosur, South America's leading trade bloc. Chávez's comments followed a rare and strongly worded interview with Obama published by the Caracas-based El Universal newspaper. The American president criticised Venezuela's business and political links...