Venezuelan President Hugo Chavez has rejected U.S. charges that he and Cuban President Fidel Castro are destabilizing forces in Latin America.

Mr. Chavez said in his weekly radio and television show Sunday that U.S. imperialism is, in his words, "the greatest threat" facing the world.

Last week U.S. Defense Secretary Donald Rumsfeld said that Venezuela and Cuba had negatively influenced events in Bolivia, where social uprisings have forced out two presidents in less than two years.

Mr. Chavez and Mr. Castro were shown side by side during the show.

Mr. Chavez had traveled to Cuba to attend the graduation Saturday of over 1,500 medical students who had studied for free on condition they would return to their communities to work.

Some information for this report provided by AP, AFP and Reuters.