The Encevo subsidiaries Enovos and Creos were last week causing disruptions to customer platforms online.

The group in a statement has now confirmed that “a number of data were exfiltrated from computer systems or made inaccessible by hackers.” But Encevo said it does not yet have the necessary information to identify and inform the clients concerned. An investigation is ongoing.

Encevo has set up a where it will provide updated information about the case, adding that customers should not contact the company as it is not yet able to provide further details.

“Once again we apologise to our customers for the inconvenience and we are doing our best to restore full service as soon as possible,” Thursday’s press statement said.

Creos manages electricity and gas network infrastructure in Luxembourg while Enovos is an energy supplier. Both companies form part of Encevo, three quarters of which are directly or indirectly owned by the Luxembourg state, with one quarter owned by China Southern Power Grid International.

The supply of electricity and gas wasn’t affected by the attack.