Lao police have seized a record haul of illicit drugs in the Golden Triangle region, two security sources in Thailand confirmed on Thursday, in what the UN said was Asia’s largest single drug bust ever.

More than 55 million amphetamine tablets and over 1.5 tonnes of crystal methamphetamine were intercepted by Laos police on Wednesday, who stopped a truck carrying beer crates in northern Bokeo, which borders Thailand and Myanmar, the sources said.

Jeremy Douglas, Southeast Asia regional representative for the UN Office on Drugs and Crime (UNODC) said the discovery was “by far the largest seizure in the history of East and Southeast Asia”.

The bust on Wednesday followed the confiscation by Lao police of a combined 16 million amphetamine tablets in two separate busts in the same area over a one week period.

Authorities in Laos did not respond to Reuters request for comment.