Three senior managers in Uber’s security unit resigned on Friday following revelations that it endured a massive security breach last year and failed to notify those affected.

A company spokesperson confirmed the resignations of the managers from Uber’s international, business operations and physical security teams. The spokesperson noted that two of the managers would stay on until the end of the year to help ease the transition process.

The managers who stepped down were Pooja Ashok, chief of staff for former Uber chief security officer Joe Sullivan; Prithvi Rai, a senior security engineer; and Jeff Jones, who handled physical security.

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Sullivan was fired from Uber last week over his role in the 2016 breach, which compromised the data of 57 million Uber users but was not made public until the end of last month.

CEO Dara Khosrowshahi has lamented the breach and its handling in a statement last week, writing that “none of this should have happened, and I will not make excuses for it.”

The massive breach has already spurred controversy over Uber paying $100,000 to hackers to cover it up. Five states and multiple countries are investigating the matter. Lawmakers on Capitol Hill including Senate Commerce Chairman John Thune John Randolph ThuneWhite House pleads with Senate GOP on emergency declaration Overnight Energy: McConnell plans Green New Deal vote before August recess | EPA official grilled over enforcement numbers | Green group challenges Trump over Utah pipelines McConnell plans vote on Green New Deal before August recess MORE (R-S.D.) and Senate Intelligence Committee ranking Democrat Mark Warner Mark Robert WarnerVirginia man charged after threatening Sen. Mark Warner Cohen grilled by Senate Intelligence panel Hillicon Valley: Senators urge Trump to bar Huawei products from electric grid | Ex-security officials condemn Trump emergency declaration | New malicious cyber tool found | Facebook faces questions on treatment of moderators MORE (Va.) have also sent letters to Uber asking for more details on the cyberattack.

Thune has said that he’s interested in holding a hearing on the breach as well.