Sprint Nextel is urging government officials to block AT&T Inc.'s planned acquisition of T-Mobile USA from Germany's Deutsche Telekom AG.

Sprint, the nation's third-largest wireless carrier, said the proposed $39 billion cash-and-stock deal would create a duopoly market for U.S. wireless services dominated by AT&T and Verizon Wireless.

"On behalf of our customers, our industry and our country, Sprint will fight this attempt by AT&T to undo the progress of the past 25 years and create a new Ma Bell duopoly," Sprint said in a statement Monday.

The Justice Department and the Federal Communications Commission could take a year or longer to review the proposed transaction.

AT&T argues that the wireless industry would still be "intensely competitive" — with multiple players in most local markets — even with the combination.