Venezuelan Vice President Nicolas Maduro says security forces have uncovered a plot to assassinate him and the head of the National Assembly, as President Hugo Chavez recovers from cancer surgery in Cuba.br br Maduro provided no proof of the claim, made at a rally on Wednesday to mark the end of dictatorship in the country 55 years ago, but he said action would be taken shortly.br br Al Jazeera's Gabriel Elizondo reports from Caracas.