A nationwide outage for CenturyLink customers, including those trying to reach 911, continues into its second day.
The outage hit 911 service across the country, according to the Federal Communications Commission, which announced Friday that it's launching an investigation.
DownDetector reported initial signs of the outage around 1 a.m. PT Thursday.
"Our network is experiencing a disruption affecting customer services," CenturyLink tweeted Thursday morning. "We know how important services are to our customers and are working to restore services as quickly as possible."
A company representative confirmed that efforts continue.
Ajit Pai, chairman of the Federal Communications Commission, ordered on Friday an investigation into the outage. He called the outage "particularly troubling" in its "breadth and duration," according to a statement he tweeted Friday morning.
The effect on people's ability to reach 911 emergency services is "completely unacceptable," he said. Pai added that he has been in direct contact with CenturyLink to emphasize the urgency of restoring service and will be monitoring progress closely.
CenturyLink didn't immediately respond to a request for comment on the FCC's investigation.
Originally published Dec. 27 at 1:47 p.m. PT.
Most recent update, Dec. 28 at 9:09 a.m. PT: Adds company comment about progress toward restoring service and Ajit Pai's comment.