By 10:30 a.m. Saturday, 10 flights departing from Brussels Airport had been canceled and 17 were delayed by more than an hour, said Ariane Goossens, a spokesperson for the airport.

Heathrow said on its website that Collins Aerospace, which provides check-in and boarding systems for airlines across multiple airports, was “experiencing a technical issue that may cause delays for departing passengers.”

A spokesperson for Collins Aerospace said the company had become aware of a “cyber-related disruption” to their MUSE software in select airports and were “actively working to resolve the issue and restore full functionality to our customers as quickly as possible.”

“The impact is limited to electronic customer check-in and baggage drop and can be mitigated with manual check-in operations,” they added.

Berlin Brandenburg airport also reported longer waiting times at check-in “due to a technical issue at a system provider operating across Europe.”

Airports advised passengers to check their flight status before coming to the airport.