In this Feb 14, 2019, file photo people stand in the lobby for Amazon offices in New York. (PHOTO / AP)

Amazon.com said cloud services offered by its unit, Amazon Web Services (AWS), were restored after a big disruption on Tuesday affected websites of the New York Metropolitan Transportation Authority and the Boston Globe among others.

Several hours after Downdetector.com started showing reports of outages, Amazon said, "the issue has been resolved and all AWS Services are operating normally."

Tuesday's impact stretching from transportation to financial services businesses underscores adoption of Amazon's younger Lambda service and the degree to which many of its cloud offerings are crucial to companies in the internet age.

AWS Lambda is a service that lets customers run computer programs without having to manage any underlying servers. The outage also affected services at the US securities regulator's EDGAR system, Southwest Airlines, the Verge and AP for Students

According to research in the past year from the cloud company Datadog, more than half of organizations operating in the cloud use Lambda or rival services, known as "serverless" technology.

Outage reports on Downdetector fell to less than 700 after having crossed 12,000 earlier in the day.

The disruption appeared smaller in time and breadth than one the company suffered in 2017 of its data-hosting service known as Amazon S3, representing the bread and butter of its cloud business.

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The outage appeared to extend to AWS's own web page describing disruptions in its operations, which at one point failed to load on Tuesday, Reuters witnesses saw.

"We quickly narrowed down the root cause to be an issue with a subsystem responsible for capacity management for AWS Lambda, which caused errors directly for customers and indirectly through the use by other AWS services," Amazon said.

AWS Lambda is a service that lets customers run computer programs without having to manage any underlying servers.

The outage also affected services at the US securities regulator's EDGAR system, Southwest Airlines, the Verge and AP for Students.

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Twitter users expressed their frustration with the outage, with one user saying "I don't know, Alexa won't tell me because #AWS and her services are down!"

Delta Air Lines also said its website was facing problems, but did not say if it was related to the AWS outage. The company did not immediately respond to a request for comment.

United Airlines said that its operations were minimally affected, adding "we're out of impact."

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Other Amazon services like Amazon Music and Alexa were also impacted, according to Downdetector.

Amazon had its last major outage in December 2021, when disruptions to its cloud services temporarily knocked out streaming platforms Netflix and Disney+, Robinhood, and Amazon's e-commerce website ahead of Christmas.

Shares of Amazon were largely flat in after-market trading on Tuesday.