New York ? A reported plot to bomb city subways with remote-controlled explosives has not been corroborated after days of investigation, law-enforcement officials said Sunday amid an easing sense of concern.

Interrogations of suspects captured in Iraq last week after an informant’s tip about bomb-laden suitcases and baby carriages have yet to yield evidence that the plot was real, officials said.

“The intelligence community has been able to determine that there are very serious doubts about the credibility of this specific threat,” Homeland Security Department spokesman Russ Knocke said. “This is after ongoing review and analysis.”

Homeland Security officials have been skeptical about the threat since it was publicly announced Thursday, but officials who were more assertive about the potential danger last week also appeared to be softening their assessment.

A Homeland Security memo said the attack might have been planned to take place on or around Sunday.