Services such as YouTube, Gmail and Snapchat, which use Google's technology, were restored Sunday around 7 p.m. ET (4 p.m. PT) after experiencing several hours of outage that appeared contained only to parts of the United States.

Google had said it was experiencing high levels of network congestion in eastern U.S., which affected multiple services in Google Cloud, G Suite and YouTube. Apple, which uses Google Cloud for some of its services, was also reporting issues with applications ranging from iMessage to iCloud.

The exact cause of the outage is not immediately known.

"We will conduct an internal investigation of this issue and make appropriate improvements to our systems to help prevent or minimize future recurrence," Google said. "We will provide a detailed report of this incident once we have completed our internal investigation."

The incident began at about 12:25 p.m. PT. Users began reporting that they were unable to access certain services.

Snapchat said it was aware that some users were unable to use the app.



We're aware of an issue preventing some Snapchatters from using the app Hang tight!



Users took to Twitter to report that YouTube was also experiencing issues.

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There were also numerous complaints that Gmail was not functioning.

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Last October, YouTube experienced a major outage around the world.

— CNBC's Saheli Roy Choudhury contributed to this report.