US claims Russian spies behind the SolarWinds hack reportedly launched a phishing email attack on 150 organizations including federal government agencies.
The actor Nobelium targeted around 3,000 email accounts across 24 countries.
A quarter of the email accounts belonged to organizations working in human rights and international development, Microsoft corporate vice president Tom Burt wrote in a blog post.
The cyberhack was reportedly conducted by Nobelium – the same actor that carried out the attacks on SolarWinds customers last year.
The spies gained access to an email service used by USAID - United States Agency for International Development.
Most of the attacks were blocked and Windows is in the process of contacting customers that were affected.
The number of successful intrusions remains unknown.
Mr. Burt tweeted: “This week we observed new nation-state cyberattacks targeting government agencies, think tanks, consultants, and non-governmental organizations. These attacks aren't slowing, and we must do more to stop them."