In a statement, Microsoft Corp disclosed, a hacking group called “Thallium” has taken control of web domains to steal nuclear related data.

In a blog post, Microsoft stated, Thallium, believed to be operating from North Korea, targeted government employees, university staff members, think tanks, and individuals working on nuclear proliferation issues, among others.

Most of its targets were located in South Korea, Japan and in the United States, said Microsoft.

Thallium tricked their victims through “spear phishing”, the technique uses credible-looking emails that appear to be legitimate at first glance.

In its complaint to the U.S. District Court for the Eastern District of Virginia, Microsoft stated, Thallium has taken control of 50 web domains.

The hacking group also used malware to compromise systems and steal data.

Thallium is the fourth hacking group allegedly backed by a nation-state, against which Microsoft has taken legal action.