The FBI is investigating an FDIC security breach that senior FDIC officials believe was sponsored by China's military, Reuters reports.

The breach, which began in 2010 and lasted several years, allowed hackers to access dozens of computers, including the workstation of former FDIC Chairwoman Sheila Blair.

In November, the breach was the target of a congressional committee probe, and the FDIC allowed congressional staff to view internal communications. In the exchanges, officials claimed the attacks were carried out by Chinese military-sponsored hackers. The exchanges did not explain why FDIC officials believe the Chinese military was behind the attack.

Reuters said it was not able to determine when the hackers were expunged from the FDIC network. The FDIC hired Mandiant, a firm specializing in probing Chinese military hackers to investigate in 2013, according to Reuters.

It is unknown if the FBI probe of the hack could result in action against China. The FDIC reported to Congress that at least seven major cyber-security incidents occurred in 2015 or 2016.