A nationwide outage of 911 service affected AT&T Wireless customers for about 90 minutes Wednesday night, including service in the District and suburban jurisdictions.

“Aware of issue affecting some calls to 911 for wireless customers. Working to resolve ASAP. We apologize to those affected,” the company said on its Twitter account about 9:45 p.m.

About 10:30 p.m., the Twitter account posted: “Issue has been resolved that affected some calls to 911 from wireless customers. We apologize to those who were affected.”

The company did not immediately release any information on what may have caused the outage or how it was restored. It also was unclear how many people in the region were affected by the 911 outage.

District officials responded to the outage about 9 p.m. and created an alternate number for AT&T customers, said Alan Etter, a spokesman for the city’s Office of Unified Communications. District users were urged dial 202-373-3700 and select option 1 for emergency service, Etter said.

Alexandria also reported the outages and urged their residents to call 703-746-4444 or text 9-1-1, city police said on their Twitter account.

In Montgomery County, officials said they hadn’t gotten any reports of issues, but they asked callers to try to use a different carrier or dial 301.279.8000.

And in Prince George’s County, police spokeswoman Jennifer Donelan tweeted “Nationwide AT&T outage now affecting Prince George’s County 9-1-1: Residents w/AT&T DIAL 301-352-1243 for emergency assistance. @PGPDNews.”

Prince William County authorities asked to call their communications number at 703-792-6500.

No immediate cause was released for the outage, and it was not clear when 911 service would be restored for AT&T Wireless customers.

This story has been updated.