AT&T, whose 5G network covers around 290 million people across the United States, grappled with interruptions to its service for more than 10 hours on Thursday.

AT&T restored wireless service late on Thursday, saying it believed the issue had been caused "by the application and execution of an incorrect process used as we were expanding our network."

AT&T said on Saturday it was crediting impacted consumers for the average cost of a full day of service.

"We recognize the frustration this outage has caused and know we let many of our customers down," the company said. "We’re also taking steps to prevent this from happening again in the future."

A company spokesperson was unable late Saturday to offer an estimate of how many customers were impacted by the outage.

The Federal Communications Commission said on Thursday it was investigating the incident, while the U.S. Cybersecurity and Infrastructure Security Agency is working with AT&T to understand the cause. AT&T said on Thursday it did not believe a cyber attack caused the outage.

The outage impacted people's ability to reach emergency services by dialing 911, according to posts on the X social media platform by government departments in several U.S. cities.

In 2021, regulators settled for $19.5 million a probe into a June 2020 T-Mobile outage that lasted over 12 hours and led to more than 20,000 failed 911 emergency calls.

In that case, the FCC estimated "over 250 million calls ... from other service providers’ subscribers to T-Mobile subscribers failed due to the outage" and "at least 41% of all calls that attempted to use T-Mobile’s network during the outage did not complete successfully."