Cash machines are going down across Europe due to a huge cyberattack that has taken down thousands of computers across the Ukraine, Russia, France, Spain and India.

In the Ukraine, The National Bank of Ukraine, Oschadbank, Sberbank, Ukrsotsbank, Ukrgasbank, OTP Bank and PrivatBank have been hit, affecting internal banking operations as well as the ATM cash machines, which also run on Windows PCs.

"The National Bank of Ukraine has warned banks and other financial market participants about an external hacker attack on the websites of some Ukrainian banks, as well as commercial and public enterprises, which was carried out today," the bank said in a statement.

"As a result of these cyberattacks, banks experience difficulty in servicing customers and performing banking operations. All the financial market participants have taken steps to tighten security measures to counteract these hacker attacks.

"The NBU is confident that the banking infrastructure is securely protected from cyberattacks and any attempts to perform hacker attacks will be efficiently warded off."

In addition to banks, airports in Ukraine have also been hit, according to Pavel Ryabikin, deputy head of the Ukraine's Ministry of Transport and Communications, who warned travellers to contact their airlines before heading to the airport.

Danish logistics firm Maersk also confirmed that its IT systems were also down due to the attack.

Cybersecurity researchers believe that the Petya ransomware (packaged as "PetrWrap") is behind the attack, using code from a leaked NSA exploit called EternalBlue to help spread the malware faster.

"It appears that today's Petya outbreak is aimed at systems that are vulnerable to EternalBlue," Abacode Cybersecurity's chief executive Michael Ferris told IBTimes UK.

"This is an especially malicious type of ransomware because it doesn't just try to encrypt data files, it tries to encrypt the entire file system. It would appear that today's outbreak is aimed at banks, critical infrastructure, power grids, Healthcare facilities etc."