Iran has seized 8.8 tons of narcotics destined for Europe and uncovered one of the country's largest trafficking rings, police said on Thursday.
"This huge narcotics shipment, which was hidden in a petrol tanker and reached here via Iran's eastern border, was supposed to be offloaded and then smuggled to European countries," state television reported from the northwestern city of Urmia, not far from the Turkish border.
Iran's deputy police chief Ayoub Soleimani said the shipment comprised 3.5 tons of morphine and 5.3 tons of opium.
He said that nine suspected traffickers were arrested with an additional 20kg of heroin and 130 firearms in their possession.
Neighbouring Afghanistan produces some 90% of the world's opium, which is extracted from poppy resin and refined to make heroin and morphine.
Iran is a major transit route for Afghan-produced opiates headed to Europe and beyond.
It confiscates and destroys hundreds of tonnes of illicit narcotics every year.
According to the latest UN figures, Iran accounted for 91% of the world's opium seizures and 20% of heroin and morphine seizures in 2017, amounting to 630 and 39 tons respectively.
Iran has repeatedly threatened Europe that if it does not do more to mitigate the impact of US sanctions on its economy, it could invest less in combating drug trafficking.
Washington unilaterally withdrew from a landmark 2015 nuclear deal between Tehran and major powers last May and reimposed sanctions on key sectors such as oil and banking.
"Despite the international pressure and economic sanctions, Iran is still the world's bulwark against drug trafficking," state television said.