Hackers launched blistering attacks Tuesday against companies and agencies across Europe.
Major global firms are reporting they’re under attack, including British advertising agency WPP, Russian oil and gas giant Rosneft and Danish shipping firm Maersk.
“IT systems in several WPP companies have been affected by a suspected cyber attack,” said WPP on its official Twitter account.
Maersk issued a similar statement, saying its IT systems “are down across multiple sites and business units due to a cyber attack.”
The U.S.-based pharmaceutical firm Merck also said it’s been hit.
“We confirm our company’s computer network was compromised today as part of global hack,” it said on Twitter.
The source of the attack is not yet clear.
The Moscow-based cybersecurity firm Group IB estimates that a virus, called Petya, has affected about 80 companies in Russia and Ukraine.
Group IB said the ransomware infects and locks a computer, and then demands a $300 ransom to be paid in bitcoins.
Ukrainian companies and government agencies seem to have been hit particularly hard.
Ukraine’s central bank is warning financial firms across the country that an unknown virus has hit the sector, creating problems for banks and customer service.
Officials at that country’s postal service and metro system in Kiev were also reporting hacking problems.
Ukraine’s vice prime minister, Pavlo Rozenko, tweeted a screenshot of his malfunctioning computer saying computers at the Cabinet of Ministers have been affected.