A major network outage on Friday hit IT systems around the world. Microsoft says the glitch was from a software update to its Windows operating system released by US cybersecurity firm CrowdStrike. The CEO of CrowdStrike said on X that the event was "not a security incident or cyberattack."

The disruption has impacted hospitals, grounded flights and locked millions of people out of the electronic devices they rely on.

Authorities in the US have responded to the outage by notifying major airlines that they will not allow them to fly. The AP says about 1,500 flights have been cancelled and nearly 4,000 delayed.

A passenger at LaGuardia Airport in New York recalled a conversation she had with her airline: "They let me know that my flight was cancelled and that they can't rebook it for the day because it's likely that more flights later on will get canceled. And then, so I can try for tomorrow, but they said it's best to just leave."

New York Mayor Eric Adams assured New Yorkers that they are safe and said at a news conference that critical infrastructure and emergency operations "are all in place."

The outage has disrupted operations at transportation hubs around the world, including Narita Airport near Tokyo.

A passenger there said: "We were so excited to fly to Okinawa and have been waiting for a long time. But the flight was canceled and now we are very sad."

The organizers of the Paris Summer Olympics, which begin in just one week, also took a hit to their operations. Media outlets say they are having a hard time delivering uniforms and official accreditations.

Microsoft executives say they have "fixed" the "underlying cause" of the problem, adding that they have "mitigated" the issue and "recovered" the affected apps and services. CrowdStrike's CEO told NBC he and his company are "deeply sorry."