Japan's Sankei Shimbun newspaper says North Korea's shadowy narcotics trade brings in some five-hundred million U.S. dollars a year for the Pyongyang regime.

Quoting a report issued by the U.S. Congressional Research Service, the paper said Wednesday that reinforced efforts led by the U.S. to crack down on drug-related crimes around the world had led to an increase, rather than a decline, in the North's export volume of narcotics.

The reports also say that tightened regulation of drug-related crimes had led the North to network with crime organizations in neighboring countries, resulting in an increase of drug exports, particularly in the past two years.

The daily added that the five-hundred million dollars in foreign currency earned through drug trading is generally appropriated for military and government operational fees.