Cuba, retaliating for an incident last week, has prevented a U.S. delegation investigating possible security breaches at the American diplomatic mission in Havana from flying to the communist island nation and furthering their probe, officials said.

Rep. Dan Mica, D-Fla., chairman of the House subcommittee on international operations, five Foreign Affairs Committee aides and a State Department official were to fly to Havana Tuesday and return Friday. But the Cuban government canceled their visas Tuesday, said John Gersuk, Mica's press aide, and Richard McBride, the subcommittee staff director.The delegation planned going to Havana to investigate possible security leaks at the U.S. Interests Section in the Swiss Embassy. Last year the Cuban government reported using several double agents to uncover alleged anti-Cuban plots by the CIA.