A cellular outage early Thursday hit thousands of AT&T users in the United States. About 70,000 outage incidents were reported around 10 AM ET, according to Downdetector. The outage disrupted calls, texts, and emergency services in major cities like San Francisco. The cause was unclear, but AT&T said it was working to restore service. Some 911 calls couldn't go through due to the outage, according to officials. Verizon and T-Mobile reported a few thousand outages each, likely from calls to other networks. AT&T shares fell around 2% following the reports of service disruptions.