* Operation involved undercover agents who infiltrated mob
* Drugs were to have been shipped to Italy from Guyana
* Investigators say Calabrian 'Ndrangheta wants to expand in U.S. (Adds details of the investigation)
By Philip Pullella
ROME, Feb 11 (Reuters) - Police in Italy and New York broke up a major trans-Atlantic mafia ring on Tuesday, arresting 24 people accused of plotting to move hundreds of millions of dollars in drugs between South America, Italy and the United States.
The sting operation involving undercover agents and wire taps offered more evidence the Calabria-based 'Ndrangheta had overtaken its Sicilian cousin, the Cosa Nostra, and was trying to make inroads in the United States by forging ties with one of the traditional New York mob families, the Gambinos.
FBI and Italian agents jointly carried out "Operation New Bridge" simultaneously just after midnight in Brooklyn, New York, and just before dawn in Italy, American and Italian officials told a news conference in Rome.
Those arrested were accused of international drugs trafficking, money laundering and membership in organised crime.
The clans of the Calabrian 'Ndrangheta, a version of the Sicilian Mafia on the southern mainland, and members of the Gambino Mafia family in New York, were in the advanced stages of plans to smuggle some 500 kg (1,000 pounds) of pure cocaine from Guyana in South America to the port of Gioia Tauro in Calabria.
Italian investigators estimated the street value of the cocaine after cutting at about 750 million euros (US$1 billion).
The drugs, supplied by Latin American drug cartels, were to have been sent to Italy hidden in shipments of canned fruit. Some of it would then have been smuggled to the United States.
"The 'Ndrangheta determined to move deadly narcotics across international boundaries, attempting to build a bridge of criminality and corruption to stretch from South America to Italy and back to New York," said Assistant U.S. attorney Marshall Miller.
He told reporters at a news conference at the headquarters of Italy's anti-Mafia investigators with other U.S. and Italian investigators that the operation struck at "the heart of international organised crime".
The operation began in 2012 when investigators detected a plan by members of the Ursino clan of the 'Ndrangheta to smuggle large amounts of drugs.
An undercover agent was dispatched to Italy and was successful in infiltrating the clan. An undercover agent was also involved in the handover of 1.3 kg of heroin in New York as part of the infiltration operation.
They said the plan involved 'Ndrangheta members in both Italy and New York who had forged an alliance with the Gambino family of the U.S. Mafia.
The 'Ndrangheta organization was "willing to work through familial connections to work hand in glove with other crime families," Brooklyn U.S. Attorney Loretta Lynch said in a Tuesday conference call with reporters. Lynch's office is prosecuting those arrested in New York.
According to prosecutors, Franco Lupoi of Brooklyn, who was arrested in the probe, is related through marriage to Nicola Antonio Simonetta, a suspected Italian member of 'Ndrangheta's Ursino clan.
Simonetta visited Lupoi in Brooklyn in 2012 to discuss the details of the alleged heroin shipment plan, said George Venizelos, assistant director of the Federal Bureau of Investigation's New York field office.
The FBI and Italian investigators intercepted email messages between mobsters in Italy and the New Socco Enterprise fruit canning company in Georgetown, Guyana.
During the investigation police wire taps indicated the group was also considering arms trafficking on a considerable scale but that plan never moved beyond the initial stages.
Investigators have said that in recent years 'Ndrangheta clans have made inroads in criminal activity in northern Italy and elsewhere in Europe, particularly in Germany, and now want to expand in the United States.
"What we see here is 'Ndrangheta attempting to gain a foothold in the New York area and the United States," Miller said. "We also see efforts to forge cooperation between the 'Ndrangheta and the Cosa Nostra," he said. ($1 = 0.7327 euros) (Reporting by Philip Pullella; Additional reporting by Chris Francescani in New York; Editing by Ralph Boulton, Toni Reinhold)