Cuba's vice president said Saturday that Fidel Castro is recovering satisfactorily from surgery and the communist leader sent his "fraternal greetings" to the people of Bolivia, Cuban state media reported. Carlos Lage spoke in Bolivia on the way to the Sunday opening of a convention to write a new constitution for the South American nation, according to Cuban international news agency Prensa Latina, which offered no further details of his statement. Neither of the Castros has been seen since Monday's announcement that Fidel, 79, had undergone surgery for intestinal bleeding and was temporarily ceding power to his brother Raul, the 75-year-old defense minister.The island's communist government beefed up security, mobilizing citizen defense militias and asking military reservists to check in daily because of what it says are fears of a U.S. attack during Castro's health crisis. The White House has insisted no such threat exists, with press secretary Tony Snow dismissing the suggestion that the United States would attack the island as "absurd."