CHIANG MAI, Thailand Thailand called on Saturday for Myanmar to help tackle the drugs trade and suggested that Myanmar take action against an ethnic minority militia group responsible for a flood of narcotics into Thailand.

Thai Prime Minister Thaksin Shinawatra said Myanmar's military government appeared confused about its relationship with the United WA State Army (UWSA) militia group, which has been branded a major producer of heroin and methamphetamine by U.S. and Thai anti-narcotics agencies.

"There are many different ethnic groups in Myanmar and Yangon is still confused over the roles and relationship with the WA, Thaksin told reporters on the sidelines of a tourism industry meeting in the northern Thai city of Chiang Mai.

"If Yangon thinks the WA, which we believe is a major drug producer to Thailand, is just a (rebel) ethnic group, that's fine. But if Myanmar accepts that they belong to the country, the Myanmar government must help us handle the drug issue."

The WA are a minority group from northeastern Burma's Shan State.

The UWSA was formed by WA fighters who mutinied against their leaders in the antigovernment Communist Party of Burma in 1989, set up their own force and then signed a cease-fire agreement with the Yangon military government.

The UWSA has helped the Myanmar Army in its fight against separatist Shan guerillas but the Yangon government says it has no control over the actions of its ally.

Thailand, once notorious for being a major conduit and supplier of heroin, now faces a growing problem with methamphetamines flooding in from Myanmar.

Thai anti-drugs agencies have estimated the number of drug addicts may this year reach four million, up from 2.7 million in 1993, and out a population of 62 million, unless more is done to tackle the problem.

Relations between Thailand and Myanmar soured earlier this year when their troops clashed at the border and each government traded accusations that the other was supporting the drugs trade.

But the two countries said they had patched up their differences after a meeting of senior officials earlier this month.

But their relations hit a new snag on Friday when Thai soldiers in the northern border town of Mae Sai blocked 44 trucks carrying lignite power generation equipment and materials from China destined for the nearby Myanmar town of Tachilek.

Thaksin said on Saturday he had ordered the shipment be halted because Thai security forces believed most of the supplies were bound for the UWSA's headquarters in Mong Yawn, 80km (50 miles) southwest of Tachilek.

Thaksin said Thailand was ready to cooperate and let the trucks cross the border into Myanmar if Yangon could prove that the equipment belonged to the government, not the WA, Reuters reported.