Sprint is again urging regulators to block AT&T’s $39 billion acquisition of T-Mobile USA, calling the deal “anti-competitive” in a statement issued Monday afternoon.

AT&T’s merger with T-Mobile USA would make it the largest wireless operator in the country and leave Sprint in a distant third place behind Verizon Wireless.

“This transaction will harm consumers and harm competition at a time when this country can least afford it,” said Sprint government affairs executive Vonya McCann in a statement. “Sprint will fight this attempt by AT&T to undo the progress of the past 25 years and create a new Ma Bell duopoly.”

The company’s statement yesterday was the second it has issued since news of the deal broke on March 20.

If AT&T’s acquisition of T-Mobile is approved, the companies’ combined customer base would top 120 million subscribers, and AT&T and Verizon Wireless would hold nearly 80 percent of the U.S. wireless market. Sprint’s subscriber base currently stands at 52 million wireless subscribers, less than half of AT&T’s subscriber base under the proposed deal.

Sprint said the deal would reverse nearly three decades of competition-inducing regulations and entrench what it called AT&T’s and Verizon’s “duopoly control” over the U.S. wireless industry.

AT&T defended the proposed acquisition, calling it “intensely competitive” and citing a report which found that there are five or more competitors in 18 of the top 20 markets in the country. 

“The AT&T/T-Mobile merger will improve quality for consumers, provide a near-term solution to impending spectrum exhaust in some markets, and expand the availability of LTE to 95 percent of Americans, spurring innovation and economic growth,” an AT&T spokesman said.

AT&T’s purchase of T-Mobile must be approved by the FCC and Department of Justice (DOJ). The deal comes amid wider government concerns about the competitiveness of the U.S. wireless industry and is likely to face considerable scrutiny from regulators and lawmakers.

Already, Congressman Ed Markey (D-Mass.) has called for hearings on the deal.