Myanmar soldiers swooped on several illicit drug laboratories to seize nearly $27 million worth of narcotics, chemicals and equipment, military newspaper The Myawady said on Monday, the biggest bust so far this year.

Photos showed hundreds of barrels, bags and other containers recovered in the operation in what is believed to be the world’s largest methamphetamine producing nation.

Troops raided several sites over the weekend in Kutkai township of eastern Shan state after receiving a tip-off, the newspaper said.

They found around 18 million tablets, about 33kg of heroin and 281 barrels of acids hidden in a ground pit alongside other equipment, including stoves, tablet-making machines and vehicles.

“It’s the biggest seizure this year,” a police officer from the anti-drugs department said, asking not to be named.

Myanmar’s multi-billion dollar drug industry is centred in Shan in the country’s east, where the poppy-covered hills also hide illicit production labs.

High-grade crystal meth, often known as ice, is smuggled out of the country to lucrative markets as far away as Seoul, Tokyo or Sydney.

Meanwhile, there is a booming regional market for lower quality tablets known as yaba that have also become increasingly popular within Myanmar.

A study by the UN Office on Drugs and Crime says that Southeast Asia’s crime gangs are netting more than $60 billion a year, a conservative estimate, according to experts, thanks to a sophisticated smuggling and money-laundering operation.

Myanmar seized an estimated $374 million worth of drugs last year, according to figures by the anti-drugs department.