US tech giant Microsoft has pointed the finger at China amid a wave of cyberattacks on firms and government agencies worldwide, announcing on Tuesday that it has identified three Chinese hacker groups responsible for the damage so far.

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

Chinese hackers breached the U.S. National Nuclear Security Administration through Microsoft SharePoint, with the Energy Department confirming no sensitive information was stolen.

The zero-day vulnerability — which was first disclosed late Saturday — has been exploited by several Chinese state-aligned groups, according to Microsoft.