Large swathes of the U.S. were hit by a cellular outage early on Thursday, with thousands of users reporting disruptions with the services offered by telecom firms including AT&T (T.N), opens new tab.

More than 32,000 outage incidents were reported with AT&T's service around 4:30 a.m. ET, according to data from outage tracking website Downdetector.com. Impacted cities included San Francisco, Houston and Chicago, the website showed.

Users of Verizon (VZ.N), opens new tab, T-Mobile (TMUS.O), opens new tab and UScellular also reported issues with the telecom firms' services, according to Downdetector.

The companies did not immediately respond to Reuters requests for comment on the reason behind the outages.... Read More: Reuters