The attack comes at the same time security firms are warning of a destructive new malware threat called , which is being directed at companies in the energy sector.

In an , Symantec described Shamoon as a threat being used in "specific targeted attacks against at least one organization in the energy sector." Symantec has not identified that firm so far.

Aramco itself has acknowledged a network disruption and said it was caused by a virus that infected PCs at the company. So far, though, Aramco has not provided any details about the incident.

In a posted on its Facebook page, the Dhahran-based Saudi Aramco said it suffered a "sudden disruption" on Wednesday that affected part of its electronic network.

"The company has isolated all its electronic systems from outside access as an early precautionary measure," the company said. "The disruption was suspected to be the result of a virus that had infected personal workstations without affecting the primary components of the network."