Tons of illegal drugs and more than 1,200 suspected dealers are in custody following a 30-nation landmark narcotics crackdown covering most of the United States, Europe and South and Central America, officials say.

At a news conference that coincided with one in Bogota, Colombia, Attorney General Richard Thornburgh detailed Tuesday a massive anti-drug operation from Aug. 1-28 that involved border raids, interdiction of air carriers and boats and destruction of marijuana crops, cocaine laboratories and secret airstrips.The operation was coordinated by the International Drug Enforcement Conference, a coalition of Western Hemisphere nations dedicated to regional efforts to combat drug trafficking.

Thornburgh said the operation was the first of its kind to involve joint law enforcement efforts and sharing of intelligence among nations.

In the past, he said, "Each of the nations of the Americas has been pursuing the war on drugs in a more or less unilateral or bilateral fashion.

"There has been, to be sure, sharing of data and isolated cases of close cooperation, but never before has there been such systematic and comprehensive cooperation."

The operation "sent a message to drug traffickers in the Western Hemisphere that henceforth they will increasingly face the combined fury of the law enforcement agencies of all the nations whose people they victimize," the attorney general declared.

The project resulted in the seizure of 11 tons of cocaine, the destruction of 244 tons of marijuana, 118,000 cocaine plants, 13 cocaine laboratories, more than 1,200 arrests, the demolition of seven clandestine airstrips and the seizure of $3.8 million in illegal drug profits, he reported.

At a news conference in Bogota, John Lawn, director of the Drug Enforcement Administration and president of IDEC, stressed that the drug seizures were not the most significant aspect of the project.

"The primary success was that we were able to do this . . . in a mutually supportive way," Lawn asserted.