WASHINGTON (AP) _ The Clinton administration is nearing completion of a new strategy to attack narcotics trafficking in Colombia and hopes to deliver ``a major and unprecedented blow'' to the drug cartels starting this year, a State Department official said Tuesday.

R. Rand Beers, an acting assistant secretary of state, said the new program would require $21 million in U.S. anti-drug assistance to Colombia beyond the $30 million designated for that country in January.

Beers, testifying before the House International Relations Committee, said recent trends in narcotrafficking in South America, coupled with successes in U.S. and regional programs, offer the U.S. and its allies ``the challenge and opportunity to deliver a major and unprecedented blow to the cartels in 1988 and beyond.''

This includes a continuation of air interdiction efforts in Peru, an expansion of eradication efforts in Bolivia, eradication of coca and opium poppy in Colombia and a strengthening of law enforcement efforts to control narcotics trafficking in Colombia.

``These elements are mutually reinforcing and taken together represent the opportunity to present the traffickers with a relentless, multipronged assault on their command and control structure,'' said Beers.