(NEXSTAR) — In what may feel like déjà vu for some, customers with AT&T and Verizon say they’re having issues with their phone service, especially when it comes to trying to call one another.

User reports on DownDetector show problems began for AT&T and Verizon customers around noon CT Tuesday and have climbed over the last few hours.

A notice from Verizon says that while its network is operating normally, “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 acknowledged a similar problem, saying in a statement that the “nationwide issue…is affecting the ability of customers to complete calls between carriers. The carriers are working as quickly as possible to diagnose and resolve the issue.”

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At around 4:45 p.m. CT, AT&T clarified that while there is a “known issue affecting calls between carriers,” it is not affecting calls between its customers.

As of 4:20 p.m. CT, DownDetector showed additional user-reported problems with Cricket Wireless, which is owned by AT&T, as well as Consumer Cellular and US Cellular. Those reports have also been declining since 5 p.m. CT.

The issue also initially appeared to be impacting calls made to 911. Emergency authorities in Virginia said they were notified of a multi-state outage by AT&T, though the company tells CNN that the notification was accidentally triggered and sent.

Shortly before 5 p.m., outage reports on DownDetector began to decrease for AT&T and Verizon.

Last week, Verizon customers, primarily in the Midwest and into some Western states, reported outages with their cell service. Some told Nexstar’s KRON they were unable to make any phone calls.

In February, AT&T customers dealt with an hours-long outage that left them unable to make calls or use their cellular data. Days later, AT&T said it would automatically apply a credit of $5 to the accounts of impacted customers.

That outage was believed to have been caused “caused by the application & execution of an incorrect process used as we were expanding our network,” AT&T explained in a February statement.

Neither AT&T nor Verizon has said what is causing Tuesday’s outage.

This is a developing story, check back for updates.