Some 1.3 tonnes of compressed marijuana worth almost 30 million baht were seized in raids in Bung Kan and Chaiyaphum provinces on Tuesday and yesterday.
In Chaiyaphum, 107kg of compressed marijuana were seized in Muang district early yesterday.
The drugs were found left under a makeshift shelter near Huay Kudchuek stream in tambon Kudtum, said Pol Col Chettha Choeychum, chief of Lat Yai police station.
The drugs, worth about 1.6 million baht, might have been left by a smuggling gang after they noticed police checkpoints along the route, said Pol Col Chettha.
In Bung Kan, 41 fertiliser sacks containing 1.28 tonnes of marijuana with a face value of about 25.6 million baht were confiscated on Tuesday.
A combined team of border patrol and marine police and soldiers spotted three fishing boats travelling from Laos along the Mekong River about 5am on Tuesday.
About 20 men on board were seen carrying the sacks to a pickup truck on the riverbank, with about 10 men waiting near the vehicle. The officers emerged and the gang fired more than 20 shots into the sky before fleeing in two of the three fishing vessels, said police.
A total of 18 fertiliser sacks containing bars of compressed marijuana were found in the back of the pickup truck, 17 more sacks were scattered along the river bank and the remaining six sacks were in the fishing vessel.