Iranian hackers working to penetrate systems, businesses and governments around the world have caused damages estimated at hundreds of millions of dollars, a report said Wednesday. Researchers for tech giant Microsoft said the attackers stole secrets and wiped data from computer networks after targeting thousands of people at some 200 companies over the past two years, according to The Wall Street Journal. Microsoft did not immediately respond to an AFP query on the report. The Journal said Microsoft traced the attacks to Holmium, a group linked to Iran, and that some of the hacking was done for Holmium by another Iranian group known as APT33. John Lambert, the head of Microsofts Threat Intelligence Center, told the newspaper the attacks were "massively destabilizing events." The report said the hackers notably targeted oil-and-gas companies, heavy-machinery manufacturers and international conglomerates in many countries. In 2017, the security firm FireEye blamed APT33 for destructive malware that targeted organizations in the Middle East and elsewhere. The news comes with Tehran, according to security experts, seeking to step up its cyber capabilities amid increasing efforts by the United States to isolate the Iranian regime.