As Russia began military operations against Ukraine, key Ukrainian government websites were down early on Thursday as multiple cyber attacks hit the country.
The websites of the Ukrainian Cabinet of Ministers, and those of the ministries of foreign affairs, infrastructure, education and others, were down, reports CNN.
"In a separate and potentially more serious hacking incident hours earlier, a data-wiping tool was found on hundreds of computers in Ukraine, according to cybersecurity researchers," the report mentioned.
This raised concerns that a destructive cyberattack was unfolding amid Russia's military escalation.
"We are aware of multiple commercial and government organisations in Ukraine impacted by the destructive malware today," Charles Carmakal, senior vice president and chief technology officer for cybersecurity firm Mandiant, told CNN.
The US officials had warned that Russia will very likely use cyber operations in conjunction with military action in Ukraine.
President Joe Biden said last month the US could respond with cyberoperations of its own if Russia conducts additional cyberattacks in Ukraine.
Of all the cyber incidents, though, the destructive data-wiping tool -- known as "wiper" malware -- had the potential to be the most impactful.
The malicious code affected "large organisations" in Ukraine, according to cybersecurity firm ESET, which has multiple clients in the country, the report said.
Russian President Vladimir Putin on Thursday authorised a "special operation" in Ukraine's Donbas region.
"We are hearing reports - some unconfirmed - of explosions in other parts of the Ukraine. Loud bangs in the capital as well as Kramatorsk in the Donetsk region," BBC news reported.
