Thousands of people were affected due to cellular outage in America, users of telecom company AT&T were most affected.

A cellular outage Thursday morning affected thousands of AT&T TN 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 recorded around 7:00 a.m. ET, according to data from outage tracking website Downdetector.com.

Users of Verizon VZ.N, T-Mobile TMUS.O and USCellular also reported disruption, according to DownDetector.

T-Mobile said it experienced no outages and that its network is operating normally.

“The downdetector is likely reflecting the challenges our customers were experiencing 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.

San Francisco Fire Department social media platforms

“We are aware of an issue impacting AT&T Wireless customers from making and receiving any phone calls (including 911),” the fire department said on the forum.