The U.S. Federal Communications Commission has found AT&T's proposed US$39 billion acquisition of T-Mobile USA to be contrary to the public interest, echoing a similar conclusion in August by the U.S. Department of Justice.

The FCC, in an order released Tuesday, found the merger to be anticompetitive. The FCC is now required to send the merger request to a hearing before an administrative law judge, where AT&T and T-Mobile USA will have the opportunity to argue against the FCC's conclusion.

FCC's officials said that the deal would result in the largest single concentration in the U.S. mobile market in history.

At the same time, the FCC approved, with conditions, AT&T's application to purchase US$1.9 billion worth of spectrum in the lower 700MHz band from Qualcomm.

A trial in the DOJ's lawsuit to block the merger is scheduled to start in February in U.S. District Court for the District of Columbia. The administrative hearing at the FCC is expected to start after the DOJ trial.