A major cyberattack on the U.S. Department of Energy compromised the personal information of hundreds of employees and likely aimed at more sensitive information according to reports released by the Washington Free Beacon.

The FBI is investigating the attacks which happened two weeks ago at the Washington headquarters of the department.

China is the suspected source of the attack as hackers have tried to penetrate the Department of Energy in the past. The level of sophistication in this attack makes it likely that the hackers involved had government support and training.

“It’s a continuing story of negligence,” former Energy Department security official Ed McCallum told the Free Beacon.

The confirmation of the attack comes days after the New York Times and the Wall Street Journal were hit with a similar attack by Chinese hackers.