Over 200 kilograms of cocaine has been seized by Greek police in the harbour city of Piraeus.
Police said on Thursday that the cocaine was hidden in a refrigerated container loaded with shrimp from a South American country.
Four men aged between 36 and 64 were taken into custody.
The Greek investigators were put on the trail of the drug gang by a tip-off from the U.S. Drug Enforcement Administration.
Before their arrest, the gang had made around five million euros (5.4 million U. S. dollars) from their trafficking, the police said.
The market value of the cocaine seized is estimated by experts at around 500,000 euros.
South-eastern Europe is considered a major hub of the illicit drug trade.