U.S. Treasury says its computers were hacked by a Chinese ‘threat actor’ in a ‘major incident’ [Video]

The U.S. Treasury Department said a state-sponsored Chinese hacking operation was able to access third-party software to tap into desktop computers of Treasury employees in what the department is calling “a major incident.”

In a letter seen by NBC News, Aditi Hardikar, assistant secretary for management of the U.S. Department of the Treasury, wrote that the office was notified on Dec. 8 of the breach. The letter is addressed to Sen. Sherrod Brown, D-Ohio, and Sen. Tim Scott, R-S.C., the chairman and ranking member, respectively, of the Committee on Banking, Housing and Urban Affairs.

The information accessed by the “threat actor” included unclassified documents, according to the letter.

China denied the U.S. allegations.

“China consistently opposes all forms of hacking and is firmly against the spread of false information targeting China for political purposes,” Ministry of Foreign Affairs spokesperson Mao Ning told reporters at a daily briefing.

Hardikar wrote that the U.S. Treasury was told …