Government-backed Iranian hackers have targeted universities in Europe, the United States and Australia in recent months, consultancy PricewaterhouseCoopers has found, Dutch broadcaster NOS reported on Friday.

According to the sources of Reuters, It is unclear whether the attempts to break into computer systems, including those of three Dutch universities, were successful.

The hackers were attempting to steal academic literature and course material to use in Iranian schools, the NOS said, citing PricewaterhouseCoopers’ cyber security specialist Gerwin Naber.

Diplomatic relations between the Netherlands and Iran have been strained since the Dutch accused Tehran of plotting two political killings in the country that triggered new European Union sanctions against Tehran last year.

Tehran has denied involvement in the shooting of the Iranian dissidents in the Netherlands.

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Earlier in the last month, Microsoft Corp said it has taken control of web domains which were used by a hacking group called “Thallium” to steal information.

Thallium believed to be operating from North Korea.

Microsoft said in a blog post, and the hackers targeted government employees, think tanks.

University staff members and individuals working on nuclear proliferation issues also targeted.