President Bush has removed Thailand from a U.S. list of major drug trafficking and drug producing countries.
The White House praised Thailand for its efforts in reducing opium poppy cultivation and heroin processing.
Twenty-two countries remain on the U.S. list of major drug producers or transit points, including Burma, Laos, Vietnam and Afghanistan.
The White House accused Burma of failing to adhere to international counter-narcotics obligations.
Although North Korea is not on the U.S. list, Mr. Bush said he was concerned about the Stalinist country's links to heroin and methamphetamine trafficking in East Asia, and the possible involvement of North Korean government agents in the trade.
Information for this story is provided by Reuters and AP.