Microsoft has detected cyberattacks linked to Iranian hackers that targeted thousands of people at more than 200 companies over the past two years.

That's according to a Wall Street Journal report Wednesday that the hacking campaign stole corporate secrets and wiped data from computers.

Microsoft told the Journal the cyberattacks affected oil-and-gas companies and makers of heavy machinery in several countries, including Saudi Arabia, Germany, the United Kingdom, India and the U.S., and caused hundreds of millions of dollars in damages.

Microsoft attributed the attacks to a group it calls Holmium, and which other security researchers call APT33. Microsoft says it detected Holmium targeting more than 2,200 people with phishing emails that can install malicious code.

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Iran is denying involvement. Alireza Miryousefi, a spokesman for Iran's mission to the United Nations, says the allegations are coming from a private company and such reports "are essentially ads, not independent or academic studies, and should be taken at face value." (VOA)