Issue impacting users calling between different mobile carriers resolved

File: An exterior view of the AT&T store. (Photo by Paul Weaver/SOPA Images/LightRocket via Getty Images)

A technical issue involving the AT&T network that was impacting some users' ability to reliably connect calls on Tuesday, has been resolved, according to an AT&T spokesperson. 

AT&T told FOX Television Stations that the "interoperability issue between carriers has been resolved. We collaborated with the other carrier to find a solution and appreciate our customers patience during this period."

DownDetector.com showed complaints about AT&T service gradually increasing after around 1 p.m. ET and peaking around 5 p.m. before starting to decline.

Some T-Mobile and Verizon users were also reporting problems, but Verizon appeared to be blaming AT&T for their issues – if not by name.

"Verizon's network is operating normally," a representative wrote. "Some customers, primarily in the Northeast and Midwest, are experiencing issues when calling or texting with customers served by another carrier. We are continuing to monitor the situation."

AT&T told FOX Television Stations that 911 calls should not be impacted by the issue, but at least one law enforcement agency in Michigan said AT&T had indicated the opposite.