A cellular outage early on Thursday hit thousands of AT&T users in the United States, disrupting calls and text messages as well as emergency services in major cities including San Francisco.
More than 50,000 incidents were reported around 7:00 a.m. ET, according to data from outage tracking website Downdetector.com.
Users of Verizon, T-Mobile and UScellular also reported disruptions, according to Downdetector.
T-Mobile said it did not experience an outage and that its network was operating normally.
"Downdetector is likely reflecting challenges our customers were having attempting to connect to users on other networks," the company said in an e-mailed statement.
AT&T did not immediately respond to multiple requests seeking comment on the outage.
The outage was impacting people's ability to reach emergency services by dialing 911, a post on social media platform X from the San Francisco Fire Department said.
"We are aware of an issue impacting AT&T wireless customers from making and receiving any phone calls (including to 911)," the fire department said on the platform.
