MIAMI (AP) _ Fidel Castro let smugglers use Cuba as a way station for one of the largest cocaine shipments ever into South Florida, the accused smugglers told drug agents.

The Drug Enforcement Administration informed congressional staffers Wednesday that the smugglers' claims are being investigated, sources told The Associated Press.

The staffers were made aware of the DEA probe in anticipation of an investigative story appearing Thursday in The Miami Herald that details the accused smugglers' claims.

The DEA was cautious in its comments to congressional staff, saying the men are cooperating with a grand jury proceeding but are facing federal drug charges.

Charged are Alberto Franco Herrera, 40, a Colombian computer systems engineer; Juan Anthony Paan, 26, a fishing-boat owner; Jorge Luis Cabrera, 53, a salesman; Hector G. Pupo Sr., 53, also a salesman; and Justo Alamo, 64, who is retired.

The five men were arrested in January with a large shipment of cocaine and Cuban cigars, but it is believed only a portion of the cocaine shipment was seized, agents said.

During questioning, the suspects claimed they brought the drugs through Havana with the personal approval of Fidel Castro, the Herald reported, quoting sources.

They said a freighter from Colombia off-loaded almost 5,665 pounds of cocaine to speedboats inside Cuban waters after stopping at a Cuban port to unload a shipment of toiletries.

Among the items drug agents seized was a photo of one of the men with Castro, the newspaper reported.

The reports were immediately denounced by Jose Ponce, first secretary of the Cuban Interests Section in Washington.

``It's an outrageous lie,'' he told the newspaper. ``The Cuban government is not involved in any drug trafficking. Many people in the United States would like to build a campaign against the Cuban government in order to use it as a pretext for intervention in Cuba that could even be a military intervention.''

Federal drug agents have long investigated whether Cuban leader Fidel Castro has cooperated with Colombian drug smugglers, a claim raised by witnesses in the trial of ousted Panamanian leader Manuel Noriega.