The BBC reports the issue affected thousands of passengers at Frankfurt airport, who were hit by issues at check-in and while boarding. Domestic passengers have been advised to travel by train instead.

Reuters said Lufthansa and Germany’s national rail operator laid blame on third-party engineering work on a railway line on Tuesday (14 February) when a Deutsche Telekom fibre optic cable was severed.

"A telecommunications line failure this morning in the Frankfurt area has had a major impact on Lufthansa’s IT systems," wrote Lufthansa on its website, before issuing a string of updates via Twitter.

"As of this morning, the airlines of the Lufthansa Group are affected by an IT outage, caused by construction work in the Frankfurt region. Unfortunately, this has led to flight delays and cancellations.

"We are working on a solution swiftly. Until then we ask all affected guests flying on domestic LH flights in Germany to book a train ticket and request a refund on lh.com."

Lufthansa later confirmed its systems were back up and running again, with the operational situation poised to improve throughout the rest of the day.