Drug abuse is on the increase worldwide - despite some successes in fighting traffickers - thanks to "rich, powerful, ruthless" kingpins who corrupt officials, a top government narcotics expert said.

Mel Levistsky, assistant secretary of state for international narcotics matters, said Monday the U.S. government is concentrating its efforts to disrupt operations of foreign drug producers. He said some progress was made last year in fighting illegal drugs.Yet, Levistsky said at a news conference, major problems remain - chief among them corruption of foreign politicians and law enforcement officials bought by the drug runners.

"The traffickers are rich, powerful, ruthless and able to adapt," the State Department official said.

"There are more than enough drugs to supply the whole world - in some cases many times over," he said. "It appears that except for the United States, drug abuse is rising all over the world."

The corruption charge was underscored recently by the appointment of Bolivian Army Col. Faustino Rico Toro to the post of commander of his nation's anti-narcotics forces. The Bush administration contends that Rico Toro has been involved in cocaine trade, and it has suspended more than $100 million in aid to Bolivia.

Rico Toro submitted his letter of resignation during the weekend as his country's anti-drug chief, Levistsky said.

The State Department official unveiled an international narcotics control strategy report that describes some "successes of 1990 . . . in an otherwise dark landscape" of drug problems.

"Halting the spread of the coca crop (chief ingredient of cocaine), improving regional cooperation and dramatically increasing the quantities of drugs seized are laudable accomplishments when seen against the backdrop of previous years," the report said.

"But they are only the first encouraging signs in a continuing struggle," it said.