The Unites States Navy says personal data of 130,000 of its sailors have been stolen.
The US Navy made the announcement on Wednesday, adding that the Naval Criminal Investigative Service had launched an investigation into the breach.
“The Navy takes this incident extremely seriously -- this is a matter of trust for our Sailors," said US Navy personnel boss Vice Admiral Robert Burke in a statement. "We are in the early stages of investigating and are working quickly to identify and take care of those affected by this breach."
No malicious use of the data, stolen from a re-enlistment approval database, has been reported so far.
An unidentified Navy official told the Navy Times that the data was stolen from Career Waypoints database, dubbed C-WAY, which sailors use to submit re-enlistment and Navy Occupational Specialty requests.
The US Navy said it would contact those whose data has been exposed by phone, email and by mail.
The Navy was notified of the breach in October, when Hewlett Packard Enterprise Services said that a computer supporting a Navy contract was “compromised,” and that the names and social security numbers of 134,386 current and former sailors were accessed.