Lufthansa has suffered an “IT outage,” prompting the German airline group to delay and cancel all its flights.

“Currently, the airlines of the Lufthansa Group are affected by an IT outage,” the company said in a social media post on Wednesday morning. “This is causing flight delays and cancellations. We regret the inconvenience this is causing our passengers.”

The software error is affecting its global network. Lufthansa also operates Austrian Airlines, Brussels Airlines, Swiss and Eurowings.

The airline is now investigating whether the incident is related to a cyber attack on fellow European airline SAS, according to Bloomberg.

Various Swedish companies have recently been hit by presumed cyber attacks, including broadcaster SVT which said a group called “Anonymous Sudan” had taken credit for the attack posting on Telegram that Swedish media would be attacked as a result of Koran burnings in Sweden.

UPDATE: The airline later said the disruption was caused by construction work in the Frankfurt region.

Tags: airlines, austrian airlines, brussels airlines, cyber security, cyberattacks, eurowings, lufthansa, sas, swiss air