A gang of 15 Malaysians has been arrested in Thailand while smuggling millions of dollars worth of crystal methamphetamine and heroin by train, police said on Thursday.
Investigators said the group was moving drugs from northern Thailand to the Malaysian town of Butterworth.
"This gang chose to transport drugs by train rather than by car because transporting by car is riskier as there are several checkpoints," Pol Lt-Gen Thitiraj Nhongharnpitak, commander of the Central Investigation Bureau, told reporters in Bangkok on Thursday.
Railway police made an initial arrest on Wednesday afternoon following a tip-off, taking in two suspects allegedly in possession of 23 kilogrammes of crystal methamphetamine, or ya ice, at Ratchaburi train station.
Their detention led to subsequent raids on South-bound express train No.35 travelling from Bangkok to Butterworth, with 12 more suspects arrested and a total of 226kg of methamphetamine and 8kg of heroin seized, police said.
Three men with 35 kg of ya ice and 1.5kg of heroin were detained at Hua Hin station, and then seven men who carried 74kg of ya ice were escorted off the train at Prachuap Khiri Khan station.
The search continued and another 44kg of crystal meth and three more men were taken from the train at Surat Thani. Police then seized more crystal meth and heroin at Chumphon station.
Police said the drugs seized in the operation were worth around 300 million baht (about US$8.5 million) in Thailand, but the value would increase about 10-fold when it reached other countries.
The arrested men went by a mixture of ethnic Malay and Chinese names, according to a list provided by Thai police.
Much of the regional drug manufacturing takes place in the so-called Golden Triangle, a remote border region where Myanmar, Laos and Thailand all meet. Thailand is a known, major transit route for smugglers.
Seizures of methamphetamine have quadrupled across the Asia-Pacific region over the last five years, according to the United Nations.