WASHINGTON (Reuters) - The U.S. Justice Department is set to decide as early as next week whether to approve the $26.5-billion merger of wireless carriers T-Mobile USA and Sprint Corp, a person briefed on the matter said on Friday.

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Earlier this week, Dish Network Corp executives met with the Justice Department’s antitrust chief Makan Delrahim and Federal Communications Commission Chairman Ajit Pai as part of the government’s review of the deal, which could dramatically reshape the U.S. wireless market.

A federal filing Friday revealed Dish Chairman Charlie Ergen was among the executives who attended the meeting Tuesday, and the firm “discussed its opposition to the proposed merger of Sprint and T-Mobile as currently constructed.”

Dish “explained the need for a minimum of four nationwide mobile network operators,” according to the filing, and also discussed “the impact of the proposed merger on Dish’s market entry and its wireless buildout plans.”

Pai agreed last month to support the merger of the third- and fourth-largest U.S. wireless carriers, in part because the firms agreed to divest the prepaid service Boost Mobile.

Verizon Communications Inc, AT&T Inc, T-Mobile and Sprint control more than 98% of the U.S. wireless market and have wireless service revenues of more than $160 billion. T-Mobile and Sprint combined have more than 135 million customers, while Verizon and AT&T control two-thirds of the total U.S. wireless market.

FCC Commissioner Brendan Carr, a Republican like Pai, has said he backs the merger while a third commissioner, Mike O’Rielly, said he is inclined to support the deal.

The Justice Department wants the companies to sell off additional assets including some wireless spectrum to create a new wireless competitor before agreeing to approve the deal, the person briefed on the matter said.

Though a decision could be reached next week, the person cautioned that it may be delayed.

Justice Department and FCC spokesmen declined to comment, as did Sprint and T-Mobile.

Both the FCC and Justice Department want to create a fourth wireless competitor and Dish, Altice USA Inc and Charter Communications Inc are potential acquirers of Boost and potentially some spectrum, the person, who spoke on condition of anonymity, said.

Ten state attorneys general led by New York and California have sued the companies and parent firms SoftBank Group Corp and Deutsche Telekom AG, warning that consumer prices will jump due to reduced competition.

A status conference in the states’ case is set for June 21, but they have yet to seek a court order temporarily blocking the merger.