WASHINGTON — The Justice Department said Thursday that the F.B.I. and other federal law enforcement agencies would be required to videotape interviews with suspects in most instances, bringing the federal government in line with the practices in many state and local jurisdictions.

It is one of the most significant changes in F.B.I. policy under James B. Comey, who took charge as the bureau’s director in September. Mr. Comey’s predecessor, Robert S. Mueller III, and senior bureau officials had once opposed the video requirement, saying the tapes could reveal agents’ interrogation tactics and discourage witnesses from talking.

Senior Justice Department and F.B.I. officials have been increasingly open to the videotaping, and former prosecutors and defense lawyers have also advocated it. A former United States attorney for Arizona, who had been fired in 2007 for his opposition to the F.B.I. policy, reached out to Mr. Comey’s chief of staff last year in the hope that he would change it.

The former official, Paul K. Charlton, said federal prosecutors were unnecessarily losing cases because they were unable to present to jurors the most damning evidence available to them: videotaped confessions.