Microsoft says it will no longer use China-based engineers to support the Pentagon. But ProPublica found that the tech giant has relied on its global workforce for years to support other federal clients,

Researchers say Chinese actors, along with other criminal hackers, exploited a security flaw in SharePoint software widely used by governments and businesses.

Microsoft has warned that Chinese state-sponsored hackers have breached its SharePoint software used by the US agency responsible for maintaining and modernizing the nation’s stockpile of nuclear weapons, according to a report.

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 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.

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

A series of cyberattacks targeting Microsoft collaboration software, specifically SharePoint, have been linked to Chinese hackers and threat actors.