Driven by antitrust concerns, U.S. regulators are fighting hard to block telecom giant AT&T\'s 39 billion U.S. dollar deal to buy Deutsche Telekom’s T-Mobile USA, according to media reports Monday. The companies acknowledged that the deal was in trouble in a Thanksgiving Day announcement. They said they had withdrawn their application to the Federal Communications Commission (FCC) to join their cellphone operations, claiming the move tactical. But they vowed to continue to pursue their plan to combine No. 2 and No. 4 cellphone carriers in the United States. Analysts said the companies’ ambitions must be scaled back if they want any chance and creative deal-making is required. To address the objections of the Justice Department and FCC that a merger would be anticompetitive, AT&T could agree to sell off 40 percent or so T-Mobile’s assets to wireless rivals, they said. AT&T would take a 4 billion dollar charge against earnings — the amount in breakup fees owed to Deutsche Telekom if the deal is scrapped. Some wondered if T-Mobile can survive if the deal does not go through.