Chinese state-sponsored hackers reportedly infiltrated the U.S. Treasury Department in December, compromising systems, including devices belonging to Treasury Secretary Janet Yellen and her deputies.

Hackers accessed fewer than 50 files on Yellen’s machine.

The breach occurred via BeyondTrust, a third-party cybersecurity provider, marking what Treasury officials labeled a “major incident.”

China denied involvement, stating it opposes hacking in all forms.

This breach highlights rising cybersecurity tensions between the U.S. and China, raising concerns over safeguarding sensitive government systems.