Hackers sponsored by the Chinese state have breached a number of U.S. government institutions, including the agency responsible for overseeing the security of America’s nuclear arsenal, Microsoft warned.

The company said state-backed hacking groups were breaching systems through flaws in SharePoint, which is used by the U.S. government and companies around the world.

In ongoing hacks, Microsoft says it has identified two Chinese hacking groups taking advantage of a key software flaw.

A critical flaw in Microsoft’s SharePoint software allowed China-linked hackers to breach dozens of systems worldwide, including US federal agencies and the nuclear weapons agency. Though no classified data has been confirmed stolen,

The tech giants have evidence that Chinese hackers are exploiting the new bug, but warned "multiple actors" are also hacking into affected SharePoint systems.

After a ProPublica investigation raised security concerns, Microsoft will cease using China-based engineers for work on sensitive Pentagon cloud computing systems.

Hackers have breached about 400 government agencies, corporations and other groups, according to estimates from Eye Security.

The move comes after a ProPublica report highlighted a Microsoft program that allows foreign engineers to indirectly interact with U.S. military systems through American “escort” intermediaries.

Some of the most sensitive data the United States has to offer is currently being maintained by engineers from China, often considered, especially in the tech field, its biggest adversary.

Defense Secretary Pete Hegseth says the DOD is "looking into" a Microsoft cloud program that used Chinese engineers after an investigative report raised concerns about CCP access.