Undercover FBI agents infiltrated several major drug-trafficking cartels by offering sophisticated communications devices, and the government Tuesday charged 93 people in the United States and abroad.

Some of the gadgets provided by the FBI actually were homing devices that allowed the FBI to monitor the movements of the traffickers, a federal law enforcement source said.Among those implicated in the yearlong investigation were three reputed leaders of the notorious Colombian Medellin and Cali drug cartels, the FBI said.

FBI bureau Director William Sessions said that the operation identified traffickers seeking to import 5,000 kilograms of cocaine, 211,000 pounds of marijuana and large amounts of heroin.

He called it "the largest undercover operation ever directed toward the interworkings of the drug cartels based in Medellin and Cali, Colombia."

Sessions said, "We believe that this case, because of the positions and large numbers of those charged and arrested, will have a significant impact on the ability of these cartels to continue to import drugs into the United States and abroad."

The operation was code-named "CAT-COM" - for "Catch Communications," law enforcement officials said.

Sessions said that undercover agents "posed as experts in the communications field and provided various state-of-the-art electronic `gadgets' to the drug traffickers."

A law enforcement source said the drug dealers were seeking secure communications devices that could not be monitored, but "what they asked for and received were not the same thing."

"Some of the equipment enabled us to do some monitoring of them," this source said, suggesting the communications devices included scanners and beepers that enabled the bureau to electronically track the suspects.

Authorities said grand jury indictments were returned in Florida, involving drug networks that stretched from Miami to New York, Los Angeles and Europe. Drugs were seized in both land and sea operations, the FBI said, and bureau agents were imperiled in one case when a sailboat carrying 402 kilograms of cocaine sank, forcing a Coast Guard rescue.

People charged in the latest sweep told undercover agents they were transporting drugs on behalf of the Medellin and Cali cocaine-trafficking cartels headed by Pablo Escobar-Gaviria, Jorge Luis Ochoa-Vasquez and Jose Gonzalo Rodriguez-Gacha, the FBI said.

The FBI said that Medellin cartel member Juan David Ochoa had planned to import seven tons of Colombian cocaine via Mexico, and more than 2,000 kilograms were seized by Mexican authorities, the FBI and the Broward County (Fla.) sheriff's office.

Sessions said that besides the drug seizures, the operation led to the seizure of cash and property valued at more than $4 million.