Italian police have taken possession of more than two tonnes of cocaine in the largest drugs seizure in the country in 25 years, after a sting operation involving three other nations across two continents.

The drugs, discovered in 60 bags in a cargo container at the Port of Genoa, have a total value of €500m (£436m) and were found with the help of the British, Colombian and Spanish police.

The cocaine belongs to various drug-trafficking organisations associated with an organised armed group known as the “Gulf Clan”, which makes use of contacts in numerous European ports where drug expeditions are carried out. The container set off from Colombia and arrived in Genoa last week and was then destined for Barcelona in Spain.

To catch the traffickers in Barcelona, the Italian investigators replaced the cargo of drugs - 1,801 bricks of pure cocaine - with salt and let it continue on its journey. In the Catalan city, Spanish police arrested the alleged recipient of the shipment, a 59-year-old Spaniard.

“We had four hours to make a decision,” Maurizio Cintura, lieutenant of the Guardia di Finanza, told the Guardian. “After four hours the container had to leave for Barcelona where the traffickers were waiting for it. We therefore put 40 military in place, unloaded the two tonnes of cocaine and replaced it with 1,800 packets of salt. Then we placed GPS receivers in the load. This allowed us to arrest a 59-year-old man related to drug traffickers at Barcelona port.”

Cintura said the investigation began on 22 January in Colombia and that the seized drugs would have been marketed all over Europe. The operation, dubbed ‘‘Genoese snow’’, follows another seizure of cocaine at the port of Livorno on Wednesday.

In that case, 644 kilos of cocaine were hidden inside bags of coffee. The drugs were divided into 582 bricks inside 23 bags, hidden in one of the thousands of containers loaded on a ship flying the Portuguese flag and coming from the Spanish port of Algeciras. The value of the cocaine found in the earlier raid was around €130m.

Spanish police said that using an empty container was a new technique being adopted by criminal organisations there.

The two operations were not connected, police said, although both Italian ports seem to have become important destinations for cocaine trafficking from South America.

“The port of Genoa, along with that of Livorno, has become the new narco trafficking crossroads,” said Genoa chief prosecutor, Francesco Cozzi, in a press conference.

Prosecutors in Genoa said they were now looking into the connections between the cartels in South America and the drug traffickers in Europe. When asked about the role of the Italian Mafia in the Genoa raid, investigators said: “It is too early to say.”

The Calabrian Mafia, or so-called ‘Ndrangheta mafia, is thought to run much of Europe’s cocaine trade. A study by the Demoskopika research institute in 2013 claimed the ’Ndrangheta made more money than Deutsche Bank and McDonald’s put together, with a turnover of €53bn.