More than 100 drug offenders were arrested overnight during raids in nine provinces across the country, according to the Office of the Narcotics Control Board (ONCB).
Those apprehended were one narcotic producer, 26 drug traders, 18 drug possessors and 66 drug addicts who were taken to undergo the rehabilitation process.
More than 700 military, police and administrative officers took part in the raids, which were carried out in 32 districts of Chai Nat, Chon Buri, Chaiyaphum, Roi Et, Phrae, Uttaradit, Phetchaburi, Krabi and Trang, according to the ONCB's news briefing on Thursday on the anti-drug operation, code-named "1386".
Officers managed to seize 42,693 speed pills, or ya ba, 1,067.2 grammes of crystal meth, or ya ice, 2.6g of marijuana, 5.8kg of kratom leaves, 6.8 litres of kratom cocktail, two kratom plants, a marijuana plant and 1.2g of ketamine.
They also recovered 18 firearms and 34 rounds of ammunition during the operation and confiscated 900,000 baht worth of valuables, according to officers.
ONCB deputy secretary-general Suriya Singhakamol, who launched the operation, said officers are scaling up efforts to check courier operators as drug traders tend to capitalise on the postal service for narcotics transport.
He said most of the senders were in the northern border areas and their cargoes were on their way to Bangkok.
Pol Maj Suriya said the "1386" operation, which has been in progress since the beginning of this month, has netted four drug producers, 63 traders and 216 drug addicts.
During the entire period of the operation, 60,607 pills of ya ba, 1,490g of ya ice, 15.09g of marijuana and 6,560g of kratom, 18 guns and bullets and 900,000 baht cash have been seized.
Meanwhile, two drug traffickers were arrested, 5 million pills of ya ba were seized and 550kg of marijuana were found on an abandoned pickup truck that had crashed in Khon Kaen.
In northern Chiang Rai province, soldiers spotted a pickup truck they were looking for travelling on a road between Chiang Rai and Chiang Mai around 9.30pm on Wednesday.
Two men were seen loading several cardboard boxes onto the back of the truck. The soldiers moved in and seized a total of 13 cardboard boxes, found to contain 5 million speed pills in total.
The two men -- driver Jetsada Promso, 42, and Phet Pornathee, both from Chiang Rai -- were arrested.
The drugs were smuggled from a neighbouring country through Loei province and were on their way to dealers in the Central Plains and the South, the Ban Phai police chief said.