HAVANA, Cuba (AP) -- Former revolutionaries promised to keep fighting for Cuba on Saturday as the island beefed up security, saying it fears a U.S. attack during Fidel Castro's health crisis. The government, under the control of Castro's brother, Defense Minister Raul Castro, has mobilized citizen defense militias and asked military reservists to check in daily. 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." The Communist Party daily newspaper Granma issued a statement by the Association of Combatants of the Cuban...