MADRID (AP) — Authorities say passengers at airports around the world have suffered some delays because of a problem with check-in systems.

Terminal 3 at Heathrow Airport near London. Thomson Reuters MADRID — Authorities say passengers at airports around the world have suffered some delays because of a problem with check-in systems.

The Spain-based company Amadeus, which provides software to airports, airlines, and the tourism industry, confirmed Thursday that a network issue had disrupted some of its systems and services.

It said its technical teams had identified the cause of the problem and that services were gradually being restored.

It would not say how many airlines or airports were affected.

London's Heathrow Airport said a small number of airlines were experiencing intermittent issues with their check-in systems at airports around the world. It said there might be delays but that passengers would be able to check in.