TORONTO — Toronto Pearson International Airport says a global technology outage that’s causing disruptions around the world could lead to flight delays and cancellations throughout the day.

It says the outage is causing tech disruptions to some airlines and that travellers should contact their airlines directly for specific flight information.

Cybersecurity firm CrowdStrike says the issue believed to be behind the outage was not a security incident or cyberattack.

The issue affected Microsoft 365 apps and services, and escalating disruptions continued hours after the technology company said it was gradually fixing it.

Tracking service FlightAware says there have been seven cancellations and 29 delays involving WestJet flights today, while Air Canada has so far seen three cancellations and 19 delays.

MASSIVE DISRUPTION

The global technology outage has grounded flights, knocked banks and hospital systems offline and media outlets off air in a massive disruption that is affecting companies and services around the world and highlighting dependence on software from a handful of providers.

CrowdStrike said the problem occurred when it deployed a faulty update to computers running Microsoft Windows.

But hours after the problem was first detected, the disarray continued — and escalated.

Long lines formed at airports in the U.S., Europe and Asia as airlines lost access to check-in and booking services at a time when many travellers are heading away on summer vacations.

News outlets in Australia — where telecommunications were severely affected — were pushed off air for hours. Hospitals and doctor’s offices had problems with their appointment systems, while banks in South Africa and New Zealand reported outages to their payment system or websites and apps.

Some athletes and spectators descending on Paris ahead of the Olympics were delayed, but Games organizers said disruptions were limited and didn’t affect ticketing or the torch relay.

DownDectector, which tracks user-reported disruptions to internet services, recorded that airlines, payment platforms and online shopping websites across the world were affected — although the disruption appeared piecemeal and was apparently related to whether the companies used Microsoft cloud-based services.

Cyber expert James Bore said real harm would be caused by the outage because systems we’ve come to rely on at critical times are not going to be available. Hospitals, for example, will struggle to sort out appointments and those who need care may not get it.

“There are going to be deaths because of this. It’s inevitable,’’ Bore said. “We’ve got so many systems tied up with this.”

Microsoft 365 posted on X that the company was “working on rerouting the impacted traffic to alternate systems to alleviate impact” and that they were “observing a positive trend in service availability.”

The company did not respond to a request for comment.

CrowdStrike CEO George Kurtz posted on X that the company “is actively working with customers impacted by a defect found in a single content update for Windows hosts.”

He said: “This is not a security incident or cyberattack. The issue has been identified, isolated and a fix has been deployed.”

In the U.S., the FAA said the airlines United, American, Delta and Allegiant had all been grounded.

Airlines and railways in the U.K. were also affected, with longer than usual waiting times.

In Germany, Berlin-Brandenburg Airport halted flights for several hours due to difficulties in checking in passengers, while landings at Zurich airport were suspended and flights in Hungary, Italy and Turkey disrupted.

The Dutch carrier KLM said it had been “forced to suspend most” of its operations.

Amsterdam’s Schiphol Airport warned that the outage was having a “major impact on flights” to and from the busy European hub. The chaotic morning coincided with one of the busiest days of the year for Schiphol.

Widespread problems were reported at Australian airports, where lines grew and some passengers were stranded as online check-in services and self-service booths were disabled — although flights were still operating.

With file from The Associated Press