BANGKOK Thailand said on Monday it made its biggest drugs seizure for several years when officials boarded two fishing boats in the Andaman Sea and found heroin and methamphetamine worth over one billion baht ($23.3 million).

One of the Thai boats was carrying 100kg (220 pounds) of heroin and more than four million tablets of methamphetamine, known in its crystaline form as "ice", Thai officials said.

"The boat was carrying the drug from a neighboring country and was on the way to Singapore," Jurin Laksanavisit, a minister overseeing drug suppression efforts, told a news conference at a navy base in southern Thailand.

Jurin did not say from which "neighboring country" the drugs had come, but a Thai Navy statement said the crew, four Thais and 22 Myanmar nationals, were arrested on Sunday near the Surin group of islands along the Thai-Myanmar maritime border.

Thailand, once notorious for being one of the world's largest suppliers of heroin, now faces a serious problem with methamphetamine.

The government has said the methamphetamine problem is so serious that it threatens national security.

The Thai authorities said the seizure confirmed their assumption that drug producers in the golden triangle region, the hilly area where Thailand, Laos and Myanmar meet, have begun to transport their products by sea.

"This arrest confirms our theory that they have changed their transportation route from land to sea," Jurin told reporters.

Bangkok has repeatedly blamed ethnic minority militia groups in Myanmar for producing methamphetamine with the support of the military government in Yangon. The groups have long been blamed for producing most of the region's heroin.

The accusation is supported by international drugs agencies, which monitor trafficking in the region.

Yangon's ruling generals deny the charge, saying they are actively fighting drugs production and smuggling.

The government in Myanmar, the world's second largest producer of opium and its derivative heroin, has urged its Asian neighbors to help it fight the drugs trade.

It has also urged Thailand to stop using drugs as a political weapon, and accused Thai newspapers of frustrating some of its anti-drugs efforts.

(Reuter)