WATCH |Cybersecurity expert Gerome Billois talks about the Petya ransomware attack.
UPDATE 4:14 p.m. EST: Edward Snowden shared a tip for dealing with the cyberattack.
UPDATE 2:47 p.m. EST:
The automatic radiation monitoring system at the Chernobyl nuclear power plant in the Ukraine was affected by a cyberattack on Tuesday, CNN reported, citing a Ukrainian federal agency.
"Due to the temporary disconnection of the Windows system, the radiation monitoring in the area of the industrial site is carried out manually," the agency controlling the Chernobyl exclusion zone said in a statement.
UPDATE 1:40 p.m. EST:
The U.S. Computer Emergency Readiness Team has received "multiple reports of Petya ransomware infections occurring in networks in many countries around the world."
"Individuals and organizations are discouraged from paying the ransom, as this does not guarantee that access will be restored," the team said in a statement.
UPDATE 11:11 a.m. EST:
Pictures of the affected computers appear to show the ransomware virus, which analysts have said is called Petrwrap or Peya, demanding payment to recover access to encrypted files, The Independent reported.
The attack is similar to the WannaCry ransomeware that affected 150 countries earlier this month.
Antonov, the Ukrainian state-run aircraft manufacturer; power distributor Ukrenergo; the largest state-owned lender, Oschadbank; and the National Bank of Ukraine have all reported being affected by the virus.
“The National Bank is confident that the banking infrastructure's defence against cyber fraud is properly set up and attempted cyber attacks on banks' IT systems will be neutralised," the national bank said in a statement.
The postal service, television stations and metro in Ukraine were also hit by the ransomware.
Several other countries were affected in addition to Ukraine. Spain, France and India have reported instances of the virus, The Independent reported, and in Russia, the state-owned oil firm Rosneft and steel maker Evraz said they were targeted.
In a statement Rosneft said that "The cyber attack could lead to serious consequences, however, due to the fact that the Company has switched to a reserve control system, neither oil production nor preparation processes were stopped."
UPDATE 10:37 a.m. EST: Ukraine's official Twitter account addressed the hack.
ORIGINAL STORY: A massive cyberattack is causing disruptions across Europe on Tuesday and has hit Ukraine especially hard, with serious breaches of that country's power grid, banks and government offices.
Ukrainian Deputy Prime Minister Pavlo Rozenko posted a picture of his darkened computer screen on Twitter and said that the computer system at government headquarters was shut down.
It isn't yet clear who is behind the cyberattack, but technology experts said it "bears the hallmarks of ransomware," according to the Associated Press. Ransomware blocks access to data until a payment has been made.
Tuesday's cyberattack follows the WannaCry attack, which spread rapidly across the web. The WannaCry attack, also known as WannaCrypt, utilized leaked National Security Agency "digital break-in tools."