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OPM Director on Second Hack: We Can't Say How Many Were Affected

Katherine Archuleta said her office has not yet determined how many Americans may be affected by the second cyberattack on OPM's systems.

U.S. Office of Personnel Management (OPM) director Katherine Archuleta said on Tuesday that she has not yet determined how many Americans may have been affected by a second breach of her office, as she faced tough questioning from a Senate subcommittee.

OPM "immediately implemented additional tools" to secure its online systems, Archuleta said at the hearing -- the first of three at which she will appear this week. But the office is "still working to determine the scope of the second breach," which put deeply personal data from federal-job applicants at risk.

Related: Sen. Susan Collins May Have Had Info Stolen in Hack on Government

The pair of breaches have been embarrassing for OPM, and a growing group of lawmakers has called for Archuleta to resign as a result of the fallout.

The agency -- which screens and hires federal workers and approves security clearances for most of the federal sector -- disclosed the first breach on June 4, revealing that the personal information of more than 4 million current and former government employees may have been exposed in a hack of its systems.

Just eight days later, on June 12, OPM announced it had discovered a second breach during its investigation of the first incident. That separate breach likely involved the "Standard Form 86," in which department applicants must disclose a wealth of personal information including Social Security numbers, psychological health details and information on relatives.

"I am angry that this has even happened," Archuleta said at Tuesday's hearing. "I have worked very hard towards correcting decades of inattention and I will continue to do so."

Related: Federal Data Breach: Can the Government Protect Itself From Hackers?

Archuleta talked up OPM's moves to modernize its software and IT systems. But OPM inspector general Michael Esser warned that despite those efforts hackers were able to breach both old and new systems.

"We've been seeing breach after breach," Esser testified. "It would not surprise me to see more."

Sen. John Boozman, a Republican from Arkansas, grilled Archuleta on several details, including the time it has taken OPM to notify affected people.

"I think this is one of the most important hearings we'll have this year," Boozman said at the very end of the hearing.