Cloud-based Microsoft applications, including Microsoft Teams, went down across a swathe of the U.S. yesterday.

Users of Microsoft Office 365, Outlook, Exchange, Sharepoint, OneDrive and Azure also reported they were unable to login. Instead, they were presented with a “transient error” message informing them there was a problem signing them in.

The China-linked BlackTech cyber-spies have adopted new malicious tools in recent attacks, and they have started targeting the United States, Symantec security researchers revealed on Tuesday.

Also referred to as Palmerworm, the hacking group is believed to have been active since at least 2013. The campaign analyzed by Symantec ran from August 2019 until as recently as August 2020, and it targeted organizations in construction, electronics, engineering, media, and finance in Japan, Taiwan, the U.S., and China. The threat actor was previously known to target East Asia.