Multiple oil transport and storage companies across Europe are dealing with cyber-attacks.
IT systems have been disrupted at Oiltanking in Germany, SEA-Invest in Belgium and Evos in the Netherlands.
In total dozens of terminals with oil storage and transport around the world have been affected, with firms reporting that the attacks occurred over the weekend.
But experts caution against assuming this is a co-ordinated attack.
Belgian prosecutors say they are investigating the cyber-attack that’s affected SEA-Invest terminals including the company’s largest in Antwerp, called SEA-Tank.
A spokeswoman for the company said they were hit on Sunday with every port they run in Europe and Africa affected.
The company is working to get a back-up IT system online but says that most liquid transportation is operational.
The spokeswoman said SEA-Invest is aware of the cyber-attacks against other companies but investigations have not determined if there is a link.
Evos in the Netherlands said that at terminals in Terneuzen, Ghent and Malta have “caused some delays in execution”.
Oiltanking which stores and transports oil, vehicle fuels and other petroleum products, said it had been hacked.
The company was forced to operate at a “limited capacity” and was investigating the incident, it said.
Some reports suggest the attack on Oiltanking is ransomware, where hackers scramble data and make computer systems inoperable until they get paid a ransom.
The disruption comes as tensions remain high between Ukraine and Russia and as concern over rising energy prices grows.
But cyber-security experts caution against jumping to the conclusion that the multiple incidents are the result of a co-ordinated effort to disrupt the European energy sector.
Another possible explanation could be that all the companies use the same software for operations that may have been compromised by hackers.