LONDON − A major technology outage grounded flights, disrupted bank operations, delayed public transit systems and forced medical facilities to cancel elective surgeries around the globe Friday in an incident a cybersecurity firm blamed on a faulty system update.

CrowdStrike, a U.S. firm that advertises being used by over half of Fortune 500 companies, said one of its recent content updates had a defect that impacted Microsoft's Windows Operating System, adding the incident was "not a security incident or cyberattack."

"The issue has been identified, isolated and a fix has been deployed," said a statement from CrowdStrike. The company's CEO, George Kurtz, apologized for the disruptions in an interview with NBC's Today. Microsoft, meanwhile, said "the underlying cause has been fixed," but residual impacts will affect some of its Microsoft 365 apps and services.

In the U.S., hundreds of flights were canceled Friday morning. American Airlines, Delta Airlines and United Airlines were among those who grounded flights less than an hour after Microsoft said it resolved a cloud-services-related outage that impacted several low-cost carriers.

Public transit systems in the U.S. reported impacts. The Washington Metropolitan Area Transit Authority in Washington, D.C., said its "website and some of our internal systems are currently down," but that trains and buses were running as scheduled. In New York City, the Metropolitan Transportation Authority also said it's buses and trains were unaffected but that "some MTA customer information systems are temporarily offline due to a worldwide technical outage."

Around the world, the outages disrupted London's Stock Exchange, caused major train delays in the U.K., sent British broadcaster Sky News off air, forced medical facilities in Europe and the U.S. to cancel some services and caused disruptions at airports in Europe, Singapore, Hong Kong and India.

Travel disruptions:Over 500 US flights canceled as global IT outage prompts ground stop

Developments:

∎ Several state and local law enforcement agencies across the U.S. reported issues at 911 call centers. Such disruptions were reported in Virginia, Arizona, Iowa and Alaska, according to officials' statements and media reports.

∎ The Federal Aviation Administration said in a statement on X it's "closely monitoring a technical issue impacting IT systems at U.S. airlines" and that several airlines "have requested FAA assistance with ground stops until the issue is resolved."

∎ Dubai International Airport said on X it is operating normally following "a global system outage that affected the check-in process for some airlines." It added the affected airlines "promptly switched to an alternate system, allowing normal check-in operations to resume swiftly."

∎ German University Medical Center Schleswig-Holstein, one of the largest medical facilities in Europe said in a statement on its website that it's halting all elective procedures Friday and closing its outpatient clinics. Emergency care remains guaranteed, the statement, which cited the CrowdStrike-related outage, said.

Over 1k US flights canceled amid outage

Several U.S. carriers, including American Airlines, United Airlines, and Delta Air Lines, issued ground stops for all their flights early on Friday due to communication problems, according to the Federal Aviation Administration.

There were more than 1,100 flights canceled and more than 1,700 delays as of 8:05 a.m. ET, according to flight-tracking website FlightAware.

According to aviation analytics company Cirium, the cancellations so far represent a little over 1.9% of scheduled flights, which the firm said is "significantly higher than usual at this point in the day." Most airlines were able to resume operations as the morning progressed, but many said they expected disruptions to continue throughout the day.

Read more about the outage's travel impacts

CrowdStrike CEO apologizes for disruptions

George Kurtz, CEO of cybersecurity company CrowdStrike, apologized Friday for the disruptions and impacts caused by the outage.

“We’re deeply sorry for the impact that we’ve cost to customers, to travelers, to anyone affected by this including our company," Kurtz said in an interview on NBC's Today.

“The system was sent an update, and that update had a software bug in it, and caused an issue with the Microsoft operating system," Kurtz said. He added, “We identified this very quickly and remediated the issue. And as system comes back online, as they’re rebooted, they’re coming up and they’re working.”

Hospitals cancel non-emergency services

Mass General Brigham in Boston cancelled previously scheduled non-urgent surgeries, procedures and medical visits, according to a statement sent to USA TODAY. The hospital said it remains open for urgent health concerns and emergency department visits and will continue to treat patients currently receiving care in the hospital.

“We have dedicated every available resource to resolve this issue as quickly as possible,” the hospital said. “It is our highest priority to ensure that our patients receive the safest care possible.”

In the same area, Tufts Medical Center told media outlet WHDH it’s still assessing the outage’s effect on clinical and surgical operations.

Two hospitals in northern German cities canceled elective operations schedule for Friday but continued to provide patient care and emergency services.

– Adrianna Rodriguez, USA TODAY

Outages exposes fragility of internet infrastructure

While there were reports of companies gradually restoring their services, analysts weighed the potential of what one called the biggest ever outage in the industry and the broader economy.

"This is a very, very uncomfortable illustration of the fragility of the world’s core Internet infrastructure," Ciaran Martin, Professor at Oxford University's Blavatnik School of Government and former head of the UK National Cyber Security Centre, told Reuters.

"IT security tools are all designed to ensure that companies can continue to operate in the worst-case scenario of a data breach, so to be the root cause of a global IT outage is an unmitigated disaster," said Ajay Unni, CEO of StickmanCyber, one of Australia's largest cybersecurity services companies.

– Reuters

Outages ripple far and wide

From the United Kingdom to Singapore, the effects of tech outages were far-reaching on Friday.

British broadcaster Sky News went off-air and train companies in the U.K. reported long delays. Departure boards at several U.K. airports appeared to freeze, according to passengers who posted reports on social media.

London's Stock Exchange reported experiencing disruptions. Some hospitals also reported difficulties processing appointments and several chain retail stores said they couldn't take payments. The soccer club Manchester United said on X that it had to postpone a scheduled release of tickets.

In Australia, media, banks and telecoms companies suffered outages.

There was no information to suggest the outage was a cyber security incident, the office of Australia's National Cyber Security Coordinator Michelle McGuinness said in a post on X.

New York's Metropolitan Transportation Authority said some of its systems were offline due to a worldwide technical outage. It said MTA train and bus services were unaffected.

Spanish authorities reported a "computer incident" at all its airports.

Berlin's main airport said check-ins were delayed because of a "technical fault."

Ryanair, Europe’s largest airline by passenger numbers, warned passengers of potential disruptions which it said would affect "all airlines operating across the Network." It did not specify the nature of the disruptions.

There were reports a shipping terminal in Gdansk on Poland's Baltic coast was not operating normally.

NetBlocks, a digital-connectivity watchdog, said that the outage reported by global airlines, corporates and infrastructure services firms and others was having "minimal" impact on global Internet connectivity.

Contributing: Reuters