British advertising agency WPP were among dozens to report an issue.
"The hacking attack could have led to serious consequences but neither the oil production nor the processing has been affected thanks to the fact that the company has switched to a reserve control system", the company said.
One of the largest health networks in western Pennsylvania, Heritage Valley Health System, said Tuesday that a "cyber security incident" had affected all operations at its two hospitals and 18 satellite centers but it wasn't clear if the incident was linked to the Petya ransomware.
Like a previous attack that swept into more than 150 countries on May 12, Tuesday's virulent outbreak appeared to be powered by a US cyber weapon stolen from the National Security Agency.
Danish logistics firm Maersk also confirmed that its IT systems were also down due to the attack.
Ukrainian Deputy Prime Minister Pavlo Rozenko said on Tuesday that the government's computer network was down, and posted a picture on Twitter of a computer screen showing an error message, Reuters reported. Even though the Eset IT security company determined that Israel was affected by the attack more than most countries, Israeli security experts are not too concerned by this surprising ranking.
Researchers said the attack may have borrowed malware code used in earlier ransomware campaigns known as "Petya" and "GoldenEye".
The automatic radiation monitoring system at the Chernobyl nuclear power plant was hit by a cyberattack Tuesday and monitoring was being carried out manually, according to a Ukrainian federal agency.
Still, the attack could be more risky than traditional strains of ransomware because it makes computers unresponsive and unable to reboot, Juniper Networks said in a blog post analysing the attack.
Another cyberattack with links to the stolen cache of National Security Agency materials is spreading across Europe on June 27, targeting banks, businesses, and a Ukraine power company. "We've seen thousands of attempts to infect but only a very limited number of companies were harmed".
Several major companies said they were targeted in an global cyberattack which started in Russian Federation and Ukraine before spreading to western Europe.
A WannaCry ransomware attack shut down over 200,000 computers globally in May.
Computer systems from Russian Federation to Britain were victims of an global cyberattack Tuesday in a hack that bore similarities to a recent one that crippled tens of thousands of machines worldwide.