NAY PYI DAW, Burma – Six countries in the Mekong sub region signed an agreement Thursday (May 9th) with the UN Office on Drugs and Crime (UNODC) to co-operate in the war on drugs, calling narcotics a "significant threat" to the region, The Irrawaddy reported.

Attending the signing ceremony in Nay Pyi Daw were officials from the UNODC, China, Burma, Thailand, Cambodia, Laos and Vietnam.

Burma's eastern Shan State is viewed as a key source to the drug trade, with Ethnic Wa rebels and the United Wa State Army -- Burma's largest armed rebel militia -- viewed as the biggest drug producers in the country, according to The Irrawaddy.

"Major challenges persist: The resurgence of opium poppy cultivation, the dramatic spread of amphetamine-type stimulants, the influx of drugs new to the region and increased levels of addiction," said John Sandage, the UNODC's director of treaty affairs.

In the Memorandum of Understanding, also known as the Nay Pyi Daw Declaration, the countries agreed to tighten cross-border co-operation, boost alternative development programmes and share experiences in drug use prevention, treatment and public awareness raising exercises, AFP reported.