ROME—Italian authorities have seized a record 5.3 tonne cocaine haul being transferred between ships off the southern coast of Sicily, police said on Friday.

The consignment had an estimated value of 850 million euros ($946 million) and five people have been arrested, the Guardia di Finanza said in a statement.

Police had been tracking a ship that sailed from South America and swooped in the early hours of Wednesday, when a surveillance aircraft spotted packages being thrown from its deck into the waters of the Strait of Sicily to be collected by a waiting fishing trawler.

They stopped the trawler and found large quantities of drugs in a hidden compartment behind some panelling on the vessel. Two Tunisians, an Italian, an Albanian, and a French national were arrested.

Sicilian regional president Renato Schifani praised the operation as a blow against drug smuggling.

“Drugs are a scourge of our society fuelled by unscrupulous men who sow death by crushing hopes and destroying many families,” he said in a statement.

In April, Italian police had found almost 2 tonnes of cocaine floating at sea off eastern Sicily which they believe had been left by a cargo ship for collection.

($1 = 0.8986 euros)