(CNN) Police in Italy have confiscated a huge shipment of 14 metric tonnes (15.4 US tons) of amphetamines which they say was produced by ISIS in Syria.
Officers tracked three suspect containers to the port of Salerno in southwest Italy and found 84 million pills with a market value of €1 billion ($1.12 billion) inside paper cylinders for industrial use, the Guardia di Finanza financial police said in a statement Wednesday.
Investigators said the bust is the largest drug haul in the world in terms of both value and quantity.
Commander Domenico Napolitano, head of the financial police for the city of Naples, told CNN that the drugs were well hidden and the scanners at the port didn't detect them.
"We weren't able to see them but we knew it was arriving because of our ongoing investigations we have with the Camorra (Italian organized crime group)," he said.
"We intercepted phone calls and members, so we knew what to expect."
The Camorra bring the drugs to Italy and take a cut for helping to distribute them, Napolitano added.
The pills carried the "Captagon" logo, which "distinguishes the 'drug of Jihad,'" according to the statement.
"It is known that ISIS/Daesh finances its terrorist activities in large part with the trafficking of synthetic drugs produced largely in Syria, which has become the leading world producer of amphetamines in recent years," police said.
"According to the DEA (US Drug Enforcement Administration), ISIS makes wide use of these drugs in all the territories over which it exerts influence and controls its sale."
The group is also able to easily produce large quantities of synthetic drugs to sell on global markets, raising huge amounts of money, added police.
The investigation and bust were carried out on a decree from the Naples public prosecutor, the statement added. Police believe the drugs were intended for distribution in Europe by various organized crime groups.
"The hypothesis is that during the lockdown, due to the global epidemiological emergency, the production and distribution of synthetic drugs in Europe has practically stopped and therefore many traffickers with different organized crime groups have turned to Syria, where it does not seem to have slowed down," police said.
Brigadier General Gabriele Failla, head of the financial police in Naples and the surrounding province, told CNN that he believes a number of criminal groups may have banded together to buy the huge shipment.
Traffickers don't normally send so many drugs at once because it's too risky, said Failla, and no single group could deal with so many pills at once.
"This is a remarkable evidence of the 'nexus' between terror financing and organized crime interests," he added.
Captagon was originally the brand name for a medicinal product containing the synthetic stimulant fenethylline. It is no longer produced or used, but drugs carrying the Captagon name are regularly seized in the Middle East, according to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA).
The drug is a common stimulant in the Middle East, and is also used in some countries bordering the European Union, the organization said.
"In addition, some recent media reports have linked this drug to perpetrators of terrorist acts in Europe or terrorist groups based in areas of conflict in the Middle East," the EMCDDA added.
In 2015, CNN reported on a US official who believed that some jihadist fighters were using Captagon, which can cause a surge of energy and a euphoric high.
In addition to reportedly taking the drug themselves, militants in Syria on both sides of the fighting may also be profiting from the production and trafficking of the pills, according to the United Nations Office on Drugs and Crime (UNODC).
"(Islamic State) and al Nusra Front are also believed to facilitate the smuggling of chemical precursors for the production of Captagon," UNODC chief Yury Fedotov said at a press conference in June 2015.
The counterfeit Captagon tablets contain amphetamine as well as other chemicals, according to the UNODC.