Myanmar police say they have seized a huge quantity of illegal liquid fentanyl.

The confiscation marks the first time the drug has been found in Asia’s Golden Triangle drug-producing region.

The seizure indicates that Asia’s drug syndicates have entered into the lucrative opioid market.

According to Reuters, more than 3,700 liters of methylfentanyl was discovered by police near Loikan village.

The bust is part of Asia’s biggest-ever interception of illicit drugs, precursors and paraphernalia.

The U.N. Office on Drugs and Crime said the scale of the bust was unprecedented, with more than 130 arrests.