Technical difficulties with a check-in system used by airlines caused major delays at airports around the globe.

Spanish company Amadeus, which provides check-in software to airlines such as British Airways, Lufthansa, Qantas, and Qatar Airways, reportedly experienced issues with its Altea reservation system on Thursday morning.

READ MORE: British Airways plane evacuated at Paris CDG 'for security reason' – airport (VIDEO, PHOTO)

According to Qatar Airways, flights were affected by an outage of the “Amadeus IT network.”

Earlier, British Airways and Lufthansa also told customers that they were experiencing a similar problem.

Amadeus confirmed the disruption but said the systems were “recovered and are now functioning normally.”

“Our technical teams took immediate action to identify the cause of the issue and mitigate against the impact on customers,” it added.

This is a system outage for many airlines using the Amadeus IT network. The Amadeus technical teams are working ..1/2 — QatarAirways Support (@qrsupport) September 28, 2017

We are aiming to have all parts of our website and reservations systems available as soon as possible. 2/2 ^JR — British Airways (@British_Airways) September 28, 2017

It is a general outage, not only LH is affected. We have no info when the systems will be up & running again. /Ella — Lufthansa (@lufthansa) September 28, 2017

The outage was reported at airports from London to Melbourne.

Apparently @qatarairways system is down at @Melair . Hopefully not much delay pic.twitter.com/6apnLWt0Mk — Osama Nasir (@osamanasir) September 28, 2017

Passengers at London Heathrow are likely to face delays because of the issue, the UK airport warned.

“A small number of airlines are currently experiencing intermittent issues with their check-in systems around the world – including Heathrow,” an airport spokesperson told RT.com.

“Passengers will still be able to check-in for their flight, although the process may take slightly longer than usual. We are working closely with our airlines to help resolve the issue as quickly as possible. We apologize for any inconvenience this may cause.”

'uuuge delays at Haneda Airpot for @Qantas. They've communicated and are trying, can't ask for much more. At least there's a sick view! pic.twitter.com/v8EIspuu2r — Shane Miles (@shane___miles) September 28, 2017

A spokesperson for Gatwick Airport said a “small handful of airlines” experienced check-in problems on Thursday morning, adding that the difficulties lasted a “matter of minutes” and that the airport was now operating as normal.