The Federal Communications Commission is expected to accept the withdrawal of AT&T and T-Mobile’s merger application Tuesday, clearing the way for the companies to concentrate on their separate antitrust battle with the Justice Department.

The companies hope to win their federal lawsuit against Justice and then reapply for their merger with the FCC. The agency is also expected to announce the release a report on its findings from its merger review — a move the companies have protested.

The chairman of the FCC last week decided to send the wireless firms’ application to an administrative hearing after finding that the deal would harm the public through job losses and higher consumer prices. The move would place greater scrutiny on the deal and almost certainly make it impossible for the companies to reach their goal of closing the merger by September 2012.

According to a person familiar with the FCC’s announcement Tuesday, the agency will allow AT&T and T-Mobile to withdraw their application. But the agency is expected to also release a report on its findings from their months-long review of the deal. The person spoke on the condition of anonymity because the announcement had not been made.

The FCC will hold a call with media at 4:15 p.m. Tuesday on the decision.

AT&T and T-Mobile won’t want the report to be revealed to the public, analysts say, because the findings could influence the Justice Department’s separate lawsuit against the merger in the U.S. District Court of the District of Columbia.

The wireless giants argue that to release the report would go against FCC protocol.

Dick Wiley, AT&T’s outside attorney, called FCC Commissioner Mignon Clyburn on Tuesday, saying that the merger application has already been withdrawn and that any documents related to the agency’s review of the deal should remain sealed.

“Releasing staff workproduct concerning a matter no longer before the Commission would be unprecedented,” Wiley said in an ex-parte filing with the FCC. “In this case, the workproduct is highly deliberative in nature as it is a draft for consideration by the Commissioners that, if finalized and approved, would merely provide the basis for issues to be considered by an Administrative Law Judge. This workproduct would in no way constitute official findings of the Commission.”