NEW YORK -- AT&T said Wednesday night that an outage issue reported on wireless calls across several states had been resolved after about an hour.

Ajit Pai, the chairman of the Federal Communications Commission, tweeted Wednesday night that the FCC will investigate the root cause of the outage.

.@FCC AT&T has reported to me that 911 service is now restored. The @FCC will investigate the root cause of the outage and its impact. — Ajit Pai (@AjitPaiFCC) March 9, 2017

Earlier, an AT&T spokesperson said in a statement to CBS News that the company was “working to resolve it as quickly as possible.”

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The spokesperson did not offer details on the extent of the issue or how many customers were affected.

Authorities in at least several parts of the U.S. reported problems or warned that AT&T customers may not be able to call the emergency number. They offered alternatives for those looking to contact emergency services.

Authorities in multiple central Indiana counties said that residents who have AT&T may not be able to call 911, CBS Indianapolis affiliate WTTV reported on Wednesday evening. The issue was part of a 911 outage in the Midwest region, Lafayette police told the station. Officials in Indiana’s Tippecanoe, Madison, Clinton and Henry counties said the outages could affect their residents.

The service issue extended to Texas, according to the official Twitter page of the government of Plano, a city near Dallas.

“Have @ATT mobile service? Customers are unable to call 911,” a tweet read, urging AT&T customers to call another number if they need police, the fire department or emergency medical services.

#BREAKING Have @ATT mobile service? Customers are unable to call 911. If you need Police/Fire/EMS in @cityofplanotx call 972-424-5678 — City of Plano (@cityofplanotx) March 9, 2017

Agencies in Corpus Christi, Fort Worth and other Texas cities provided alternate numbers for people to call if they have an emergency.

Fire officials in Florida also said they were alerted to an issue.

“Orange County Fire Rescue has been notified of critical problem w/AT&T mobile service - could affect citizens attempting to access 911,” a tweet said. It advised those unable to reach 911 to call the Orange County Sheriff’s Office.

Orange County Fire Rescue has been notified of critical problem w/AT&T mobile service - could affect citizens attempting to access 911 (1/2) — OCFire Rescue (@OCFireRescue) March 9, 2017

Call 407-836-HELP to reach @OrangeCoSheriff for AT&T users unable to access 911 due to carrier issues. Additional info forthcoming. — OCFire Rescue (@OCFireRescue) March 9, 2017

Agencies in Tennessee and Washington, D.C, have also sent out tweets saying they’ve been affected by the outage and are providing different numbers to call.

At&T said in its statement: “Will keep you apprised to any new information.”