BANGKOK (AP) — Thai police have Esthenseized what is being called a record haul of methamphetamine tablets in the western province of Kanchanaburi, close to the Myanmar border.

Officers found an estimated 50 million tablets hidden in sacks in a six-wheeler truck they stopped at a joint police-military checkpoint on Tuesday. The occupants of the truck – a man and a woman – were arrested.

The quantity of methamphetamine tablets seized is a record for Thailand, Jeremy Douglas, the Southeast Asia regional representative for the United Nations Office on Drugs and Crime, said Wednesday. The region’s biggest known seizure took place in neighboring Laos in October 2021, when a consignment of 55 million pills was discovered.

“We’ve not seen major cases here in Kanchanaburi for a couple of years, and never anything like this,” Douglas said. “But it’s also not a surprise given the extreme supply being produced by militias and traffickers in northern Myanmar.”

Myanmar has historically been the region’s main drug production area in part because of lax security measures in border areas where minority ethnic groups have long been fighting for greater autonomy. Some of the powerful ethnic armed groups there have been heavily involved in narcotics production for decades.

A 2021 military takeover in Myanmar that unseated the elected government of Aung San Suu Kyi triggered armed resistance nationwide, further destabilizing the country.

The U.N. drug agency’s June 2023 report on synthetic drugs in East and Southeast Asia warned that the huge trade in methamphetamine and other illegal drugs shows no signs of slowing down.

Thailand’s Deputy Prime Minister Anutin Charnvirakul, who is also interior minister, told reporters that illegal drugs used to be smuggled into Thailand’s northern and northeastern provinces, but had moved to western provinces such as Kanchanaburi because of more intense surveillance and security along the old routes, a point the U.N. agency had also made earlier this year.

Anutin said increased combat between Myanmar’s military and its foes among the country’s pro-democracy movement and ethnic minority armed groups also increased the smugglers’ risks along their old routes.