In comments made public on Thursday, retired General David Petraeus said he did not share any classified documents with Paula Broadwell, the woman with whom he had an affair that ended his tenure as CIA director.
Mr. Petraeus also told a reporter for the HLN television network that it was the affair, not any questions over the CIA's role during the Sept. 11, 2012, attacks on the U.S. diplomatic mission in Benghazi, Libya, that prompted him to step down.
A computer used by Mrs. Broadwell contained substantial classified information that should have been stored under more secure conditions, law enforcement and national security officials said on Wednesday.
Mr. Petraeus's comments to the network occurred last week, according to Steven Boylan, who was the general's spokesman in Iraq and has spoken to him since he resigned at the CIA.
Mr. Petraeus has also been telling associates the affair did not lead to security breaches. "He told me that he had not passed any classified information to Paula or anyone else," Mr. Boylan said.
Mr. Petraeus's remarks notwithstanding, investigators on Thursday said they had not ruled out the possibility that Mr. Petraeus passed on classified material to Broadwell. They spoke on condition of anonymity to discuss an ongoing law enforcement investigation.
Mrs. Broadwell, who has not been charged with any wrongdoing, has made no public comment since the scandal erupted last week.
The developments underscored a central question hanging over a scandal that led to the downfall of one of the most respected U.S. public figures: whether a private indiscretion put national security at risk.
Some lawmakers have questioned why they were not notified of the probe until after last week's presidential election.
Attorney General Eric Holder said the FBI did not see any possible threats over the course of the investigation that were urgent enough to notify President Barack Obama or lawmakers until shortly before Mr. Petraeus stepped down.
"After a pretty critical interview occurred the Friday before we made that disclosure – when we got to that point where we thought it was appropriate to share the information – we did so," Mr. Holder said at a news conference.
Mr. Obama said on Wednesday that there was no indication so far that any classified information had been disclosed as a result of the affair.
Sources who have been briefed on the investigation said on Thursday that none of the classified material found on Mrs. Broadwell's computer came from the CIA. The material, they said, predates the start of Mr. Petraeus's tenure at the spy agency in September 2011.
As an Army reserve officer involved in military intelligence, Mrs. Broadwell had a security clearance that allowed her to handle sensitive documents. With Mrs. Broadwell's consent, the FBI searched her Charlotte, North Carolina, house on Monday evening.
Mrs. Broadwell's security clearance has now been suspended, and she could have it revoked and face harsher penalties if it is found she mishandled classified data.
Law enforcement officials have said that they believe the investigation is likely to end without criminal charges.
The scandal this week also ensnared the commander of U.S. and NATO forces in Afghanistan, Marine General John Allen.
Gen. Allen has pledged to resolve questions surrounding what officials have called his inappropriate email communications with Tampa socialite Jill Kelley, who is also at the center of the Petraeus case.
Last spring, Mrs. Kelley informed the FBI of harassing emails that were ultimately traced to Mrs. Broadwell. A subsequent FBI investigation uncovered Mrs. Broadwell's affair with Mr. Petraeus.
Traveling in Bangkok, Defense Secretary Leon Panetta said he knew of no other military officials who have been drawn into the Petraeus investigation beyond Gen. Allen. He acknowledged that further revelations were possible.
Mr. Panetta also ordered the U.S. military's top brass to conduct of review of ethics training to find any gaps that may need to be addressed.
Mr. Petraeus on Friday is due to face lawmakers who are examining the September attacks in Benghazi, Libya, that caused the death of four Americans, including the U.S. ambassador. The attack has turned into a flash point between Obama and Republicans who accuse his administration of misleading the public in the days following the attack.
The questioning will be confined to the events in Benghazi, said one lawmaker who is expected to participate.
"We'll get his perspective on what information he knew and how his assessment of that intelligence changed over time," said Democratic Representative Adam Schiff.