The FCC today stopped its 180-day shot clock on its review of AT&T’s proposed purchase of Alltel assets from Atlantic Tele-Network.

In a filing spotted by Phone Scoop, the FCC chose to delay the transaction because it said AT&T has not provided sufficient details on how it plans to transitional Alltel’s pre-paid customers. The FCC stoppage comes 175 days into the process.

Verizon bought Alltel in 2008 but in 2010 sold part of the company’s assets to Atlantic Tele-Network, which provided wireless service under the Alltel name.

In January, AT&T announced it was purchasing for $780 million the Alltel assets including wireless spectrum in the 700 MHz, 850 MHz and 1900 MHz bands as well as network assets, retail stores and approximately 585,000 subscribers.

In a statement, Jim Cicconi, AT&T senior executive vice president of external & legislative affairs, said, “AT&T is extremely disappointed at the FCC delay today on this small transaction. AT&T is ready, willing and able to make significant network investments in these rural territories to bring HSPA+ and LTE services to Allied’s customers, an investment that will not occur but for this transaction.  AT&T has actively worked to address FCC concerns and will continue to work with the Commission until all issues are resolved.”