The United States is increasingly convinced that North Korea has a direct role in global drugs production and trafficking, US President George W Bush has said.
The US has accused North Korea of drugs and arms smuggling
In his annual report to US Congress on drug-producing nations, Mr Bush identified 23 countries which the US considers to be major drug-trafficking or major drug-producing centres, including Afghanistan, Pakistan and China.
North Korea was not on the list but the US president said there was evidence that "state agents and enterprises" were involved in the narcotics trade.
The US, which has been pressuring North Korea over its nuclear ambitions, also warned that a proposed food donation to the North could be at risk because of fears it would be diverted to the military.
Mr Bush said in the report that the US would step up efforts to work with the affected countries in the region in order to prevent such trade.
Haiti and Burma 'failing'
"Although there is no evidence that narcotics originating in or transiting [through] North Korea reach the United States, the US is intensifying its efforts to stop North Korean involvement in illicit narcotics production and trafficking," Mr Bush said in his report.
"We are deeply concerned about heroin and methamphetamine linked to North Korea being trafficked to East Asian countries," he added.
The assessment also warned that Haiti and Burma had "failed demonstrably" to meet international obligations to fight drugs trafficking or production.
Mr Bush's comments come at a time of continued tension between the US and North Korea over the reclusive state's nuclear programme.
The US has repeatedly accused North Korea of illegal drugs and arms smuggling, charges North Korea has denied.
Mr Bush cited in his report the seizure of $50m worth of heroin smuggled from a North Korean state-owned ship off the coast of Australia in April as evidence of a link between the country and drugs trafficking.
On Monday the US also accused the North Korean Government of preventing international food aid reaching those for whom it was intended.
North Korea had alleged that the US and Japan had put pressure on United Nations aid agencies to stop or delay food shipments to North Korea.
However US State Department spokesman Adam Ereli said the US was concerned that international food aid intended for desperately needy civilians was being diverted to the North Korean military.
The US has said it will continue to fund a separate programme to build low-risk nuclear reactors for North Korea.
The programme is managed by the New York-based Korean Peninsula Energy
Development Organization, or KEDO.
The US said its $3.72m of funds would only be used for administrative expenses, since construction of the reactors has been suspended since the row broke out a year ago over North Korea's nuclear plans.