The newspaper was also working with Kroll, a corporate investigation firm, to restore its systems and to investigate the episode, Ms. Hughes said.
The Inquirer, in its news story on the “apparent cyberattack,” said it was the most significant disruption to the publication of the newspaper since January 1996, when a major blizzard dropped more than 30 inches of snow on Philadelphia.
The newspaper reported that Ms. Hughes, citing a continuing investigation, had declined to answer detailed questions about the episode, including who was behind it, whether The Inquirer or its employees appeared to have been specifically targeted, or whether any sensitive employee or subscriber information might have been compromised.
In an email on Monday, Mr. Benn, the company spokesman, said: “As our investigation is ongoing, we are unable to provide additional information at this time. Should we discover that any personal data was affected, we will notify and support” anyone who might have been affected.
Special Agent E. Edward Conway of the F.B.I. field office in Philadelphia said that while the agency was aware of the issue, it was the bureau’s practice not to comment on specific cyber incidents. “However, when the F.B.I. learns about potential cyberattacks, it’s customary that we offer our assistance in these matters,” Mr. Conway said in an email.