AT&T said Wednesday that some US customers are experiencing trouble placing wireless calls but rebooting the device would fix the problem.

DownDetector.com, which monitors reports of outages in real time, showed customers complaining about a lack of service across the country including in Houston, New York and San Francisco. AT&T, which also owns DirecTV, said it was aware of the issue and was working to restore services to affected customers.

"We are aware of an issue affecting some users' ability to make certain wireless calls," AT&T said in a statement. "These users should restart their devices, which should resolve the issue."

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The outage appears to have begun around 1 p.m. PT, according to DownDetector, which counted more than 6,000 customer complaints of service outages at 3 p.m. PT. Of those, 42 percent reported problems related to internet access, while 32 percent complained of phone issues.