The US started putting pressure

Soon after the Conference began, the US government learned that Luciano was in Cuba. Luciano had been publicly fraternizing with Sinatra as well as visiting numerous nightclubs, so his presence was no secret in Havana. The US started putting pressure on the Cuban government to expel him. On February 21, 1947, U.S. Narcotics Commissioner Harry J. Anslinger notified the Cubans that the US would block all shipment of narcotic prescription drugs while Luciano was there.