The largest and most successful manhunt for criminal fugitives in American history -- featuring undercover sting operations and cooperation by 50 federal, state and local law enforcement agencies in eight northeastern states -- was announced today by the U.S. Marshals Service.

The two-month effort, completed on Monday, led to the arrests of 3,309 fugitives on 5,080 outstanding felony warrants based on crimes including murder, rape, robbery and narcotics and weapons violations.

Marshals service Director Stanley E. Morris said that the operation was aimed at hard-core offenders and that there is an average of almost four previous felony convictions for each apprehended fugitive.

"This represents the largest and most successful fugitive manhunt in law enforcement history," Attorney General William French Smith said at a news conference here. "Today, Americans are significantly safer."

The program, the seventh large-scale fugitive operation run by the marshals service in the last 2 1/2 years, represents "a vital part of our expanded cooperative efforts" to fight "this cancer on American society," Smith said.

Morris said many of the fugitives were on the loose because of lax bail procedures in the courts, and he acknowledged that a number of the newly arrested criminals may be released on bail despite their records. In a similar fugitive sweep in California seven months ago, Morris said, about half of those apprehended were later freed on bail.

The operation, known as FIST 7 (Fugitive Investigative Strike Teams 7) was coordinated in secrecy from an abandoned building in Queens.

The task force was made up of 113 marshals, five agents from the federal Bureau of Alcohol, Tobacco and Firearms, who assisted in tracing firearms, and 105 state and local law enforcement officers from New York, New Jersey, Pennsylvania, Rhode Island, Connecticut, Massachusetts, Delaware and Maryland.

Several sting operations were used to pursue criminals who could not be apprehended through conventional surveillance techniques.

In one used in the New York City area, a marshal posing as a driver for the "Brooklyn Bridge Delivery Service" dropped off invoices carrying the motto, "Don't mess with the rest, come to the best," and notifying the fugitives that packages were being held for them.

Thomas Leschorn, the criminal investigator who ran the operation for the marshals and manned the telephones for the delivery service, said that when a suspect called to ask what was in the packages, he made up an item to go with the criminal's profile. For a street criminal, Leschorn said, he might say the package appeared to contain a radio.

"For a rapist, I might say it looked like a promotional package from an adult toy company," he said.

After the fugitive agreed to accept the package, the "delivery man" appeared with backup units to make the arrest. "Those guys really have bought part of the Brooklyn Bridge," Leschorn said.

Another New York City area sting, "Job Scam," involved sending letters to fugitives from a "firm" called Prior Offenders Employment Opportunities offering jobs with wages up to $15 an hour. Fugitives who agreed to an interview were required to provide identification and were arrested on the spot.

In a sting to attract younger fugitives in Hartford, Conn., word was left at their last known addresses that a radio station had awarded them two free tickets to a Boy George concert, complete with dinner for two and the use of a limousine for an evening. They were arrested when they tried to collect their prizes.

In Buffalo, more than 20 fugitives were arrested when they answered letters that claimed they had won $250 to $10,000 in a lottery.

Howard Safir, head of the marshals' enforcement operations, praised the cooperation among the law enforcement agencies, noting that day-to-day decisions were made by the agents and policemen rather than higher-ranking officials. During the effort, the state and local officers were deputized as marshals so that they could trail their fugitives across state lines.

"We took all the bureaucracy out of it, except for the initial planning," Safir said. "I consider anybody above the rank of captain is a bureaucrat . . . . We ordered that all disputes be resolved at the lowest possible level."