American officials have reportedly said that hackers with suspected links to China may have accessed sensitive data on US intelligence and military personnel available at the Office of Personnel Management (OPM).
It is being speculated that the attack could leave US security personnel or their families open for hackers to blackmail.
OPM has not commented on the reports yet.
Officials told the Associated Press, that the attackers have targeted the forms submitted by intelligence and military personnel for security clearances.
Called Standard Form-86, the documents include personal information of personnel- everything from eye colour, to financial history, to past substance abuse, as well as contact details of their relatives and guardians.
This is the second hacking attack at OPM in US in the last two weeks.