Comcast has restored services after the operator was struck with hours-long outages that affected customers in several major markets, including Chicago, Philadelphia, New Jersey and San Francisco.

Comcast acknowledged on Twitter Tuesday morning that it was dealing with "intermittent service interruptions" and later characterized the degree of interruptions as "widespread." According to the San Francisco Chronicle, some customers there were complaining about outages on Monday evening.

Figure 1:

A Comcast service vehicle on the job in February 2018. Photo by Jonathan Weiss / Alamy Stock Photo.

Comcast said Tuesday afternoon it had resolved a "network issue" that caused the outages but added that it's still investigating the root cause:

"Earlier, some customers experienced intermittent service disruptions as a result of a network issue. We have addressed the issue and service is now restoring for impacted customers, as we continue to investigate the root cause. We apologize to those who were affected," Comcast said in a statement.

The exact extent of the issue was not immediately known, as some Comcast markets, such as Denver, appear to have been spared.

Update: Light Reading did hear from customers in the Denver area who did not have access to Comcast service for several hours Wednesday. It's not clear if those were isolated issues or tied into the outages reported in other US markets.

Comcast, the nation's largest ISP, serves about 31.38 million broadband customers – 29.10 million residential customers and about 2.28 million business broadband customers.

— Jeff Baumgartner, Senior Editor, Light Reading