NEW YORK – Federal authorities orchestrated one of the biggest Mafia takedowns in FBI history Thursday, charging 127 suspected mobsters and associates in the Northeast with murders, extortion and other crimes spanning decades.

Past investigations have resulted in strategic strikes aimed at crippling individual crime families. This time, authorities used a shotgun approach, with some 800 federal agents and police officers making scores of simultaneous arrests stemming from different mob investigations in New York, New Jersey and Rhode Island.

They also used fanfare: Attorney General Eric Holder made a trip to New York to announce the operation at a news conference with the city’s top law enforcement officials.

As of late Thursday, 125 had been arrested.

Holder called the arrests “an important and encouraging step forward in disrupting La Cosa Nostra’s operations.” But he and others also cautioned that the mob, while having lost some of the swagger of the John Gotti era, is known for adapting to adversity and finding new ways of making money and spreading violence.

“Members and associates of La Cosa Nostra are among the most dangerous criminals in our country,” Holder said. “The very oath of allegiance sworn by these Mafia members during their initiation ceremony binds them to a life of crime.”

In the past, the FBI has aggressively pursued and imprisoned the leadership of the city’s five Italian mob families, only to see ambitious underlings fill the vacancies, said Janice Fedarcyk, head of the FBI’s New York office.

“We deal in reality, and the reality is that the mob, like nature, abhors a vacuum,” she said.

However, the FBI has gained a recent advantage by cultivating a crop of mob figures willing to wear wires and testify against gangsters in exchange for leniency in their own cases.

“The vow of silence that is part of the oath of omerta is more myth than reality today,” she said.

In the latest cases, authorities say turncoats recorded thousands of conversations of suspected mobsters. Investigators also tapped their phones.