Was your cellphone's data service out Thursday morning? You're not alone. T-Mobile users in many cities were reporting data outages.

Significant outages were reported in Atlanta, New York City, Baltimore, Washington, Chicago, Dallas and Houston, with smaller outages in Boston, Tampa, Miami, Minneapolis, Denver, Las Vegas, San Francisco, Oklahoma City, Nashville, San Diego and Salt Lake City.

Many users were reporting that telephone calls were still going through, but their data was not working. The national outage tracking site DownDetector.com indicated the outages began around 7 am ET, and continued to build through at least 10 am.

T-Mobile's customer service Twitter account @TMobileHelp mentioned the outage after 10 am, but did not indicate when full service would be restored.