Security firm Kaspersky Lab said the attack has hit around 2,000 computers so far in around a dozen countries. The most affected organisations are located in Russia and the Ukraine, with systems in the UK, Germany, France, Italy, the US and Poland also hit.

The researchers confirmed that one of the ways the virus spread was using the Eternal Blue tool, but that there are likely other ways too.

The company added that the ransomware might not be a variation of Petya but a new strain of the virus.

"Kaspersky Lab's analysts are investigating the new wave of ransomware attacks targeting organisations across the world. Our preliminary findings suggest that it is not a variant of Petya ransomware as publically reported, but a new ransomware that has not been seen before," the researchers said.