Wind power giant Vestas said some of its IT infrastructure and data had been “compromised” as it worked flat-out to reopen its systems after being hit by a “cybersecurity incident” on Friday.

The Danish group – one of the world’s largest suppliers of wind turbines – said in an update on Monday morning that it had started a “gradual and controlled” reopening of its IT systems after being forced to shut some down.

Vestas said it had “together with external partners worked around the clock to contain the situation and re-establish the integrity of its IT systems.