Pol Lt-General Chinnapat Sarasin, chief of the Narcotics Suppression Bureau, led a team of officers to Soi 11 on Thaweerat Road in tambon Mae Yao after receiving a tip that this was were a gang was stashing a haul of drugs, the source said.
Police then extended their raid to a petrol station in tambon San Sai where they arrested Thanathip Rattanaprajang, 51, and Phrom Rattanakrajang, 47, the source said.
Chiang Rai Governor Prajon Prachsakul will present the cache of pills and provide details of the bust at a press conference on Monday morning in City Hall, the source added.