Thai police announced Friday a huge seizure of more than five million illegal methamphetamine pills -- worth about $30 million -- believed to have been smuggled from Myanmar.
The drugs bust is one of the kingdom's largest in years and reflects soaring production of amphetamine-type stimulants in Myanmar, which is emerging from decades of military rule.
Six people were arrested in two related seizures of the pills, known as yaba -- "crazy medicine" -- found at a house in Nonthaburi near Bangkok and in a truck in the central province of Phetchabun, authorities said.
"We seized around 5.3 million yaba pills worth around one billion baht," Police Lieutenant General Surapol Thuanthong of the Narcotics Suppression Bureau told AFP by telephone.
He said the pills were produced in Myanmar and smuggled through the Golden Triangle region, where the remote edges of Thailand, Myanmar and Laos meet.
"Now production is increasing because it makes a lot of profits", Surapol said. "Minority groups have small factories to make them."
It is estimated that at least 1.4 billion yaba tablets -- with an estimated street value of $8.5 billion -- are being produced each year in the Golden Triangle region, according to the United Nations Office on Drugs and Crime.
There are an estimated 600,000 yaba users in Thailand.
The drug is mostly made in isolated mobile laboratories hidden in the forests of Shan state in Myanmar, which is also still the second-largest global source of opium after Afghanistan.
The drugs trade is closely linked to Myanmar's long-running insurgencies in remote border areas, with ethnic minority rebels widely thought to use the profits to fund their operations.