A cellular outage in the United States was reported by AT&T, T-Mobile, Verizon and other network users on Thursday, according to outage tracking website Downdetector.com.

The number of reports of AT&T outages peaked at 31,931 at around 4:30 a.m. ET, data from Downdetector, which tracks outages by collating status reports from sources including user-submitted errors on its platform, showed.

More than 800 service outages of US wireless carriers Verizon and T-Mobile were also reported on the platform.

Verizon, T-Mobile and AT&T did not immediately reply to Reuters’ requests for comment.

This is a developing story. Check back for updates.