Italian authorities have seized a record 5.3 tonnes of cocaine being transported between ships off the southern coast of Sicily, the peninsula’s police said on Friday, Reuters reported.

The haul is valued at 850 million euros, equivalent to $946 million, and five people have been arrested, the Guardia di Finanza said in a statement.

Police had been monitoring the ship, which had arrived from South America, and took action early Wednesday morning when a surveillance plane spotted packages thrown overboard into the waters of the Strait of Sicily to be picked up by a fishing vessel.

They stopped the trawler and found a large amount of drugs in a hidden compartment on the vessel. The police detained two citizens of Tunisia, an Italian, an Albanian and a Frenchman.

The president of the Sicily region, Renato Schifani, assessed the operation as a blow to the drug trade.

“Drugs are the scourge of our society, fueled by unscrupulous people who sow death, shattering hope and destroying many families,” Shifani said in a statement.

In April, Italian police discovered nearly 2 tons of cocaine floating in the sea east of Sicily, believed to have been left behind by a cargo ship that was due to be picked up.