U.S. Coast Guard and intelligence officials tell NBC News there is NO EVIDENCE that any Cubans are making preparations for a massive exodus by boat from Cuba, but according to several officials, "We're keeping a close eye on it." U.S. intelligence estimates predict it's possible tens of thousands of Cubans may attempt to flee Cuba during any possible transition of power, but there are no signs any such movement is underway.

While the Coast Guard, Homeland Security and the military have a number of contingency plans to deal with a massive boat-lift out of Cuba, none of the plans have been activated. According to an official from the Coast Guard, which would take the lead in any interdiction operation, "We haven't moved a single asset, but we're closely monitoring the situation."

A Homeland Security official says, "We have made no adjustments to our security posture at this time." One intelligence official doubts that even if there was a permanent transition from Fidel to Raoul, that the Cuban government would permit a mass migration, "because it has security implications for Cuba as well." Such a migration would be considered a direct challenge to the government's authority and control.