NEW YORK (Reuters) - Charter Communications CHTR.O submitted a proposal to the Justice Department to buy telecom assets being sold under the T-Mobile US Inc TMUS.O and Sprint Corp S.N combination, but never heard back from the agency, three sources familiar with the matter said.

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U.S. officials decided to accept a deal to sell assets including Sprint's Boost Mobile brand to satellite TV provider Dish Network DISH.O to resolve antitrust concerns, ending extensive talks on a merger the Justice Department is expected to approve this week.

The Justice Department’s lack of response to Charter could raise concerns among critics of the $26.5 billion merger of wireless carriers T-Mobile and Sprint that officials did not weigh all divestiture offers before deciding on a deal with Dish.

Details of the proposal were not immediately known, but sources said this week Charter had requested that there be an auction process for the divested assets.

The Justice Department and Charter declined to comment.

Ten state attorneys general, led by New York and California and including the District of Columbia, filed a lawsuit on June 11 to stop the merger, saying it would cost their subscribers more than $4.5 billion annually. Four more states have since joined the lawsuit.

The lawsuit alleges that the merger will reduce competition in the wireless market and be particularly harmful to low-income and rural Americans.

Dish emerged as the leader to acquire the prepaid phone brand Boost Mobile, which T-Mobile and Sprint are selling in order to gain regulatory approval for their merger. Charter began offering its own mobile service called Spectrum Mobile last year, which runs on Verizon Communications’ VZ.N network. It served 310,000 mobile lines as of the first quarter.

Dish, which has been stockpiling billions of dollars worth of wireless spectrum, faces a March 2020 deadline to build a product using the spectrum in order to fulfill the requirements of its licenses. It has focused on building an Internet of Things network, with the goal of eventually having a 5G wireless network.

The Federal Communications Commission has indicated it is prepared to approve the Sprint and T-Mobile merger.

The Justice Department has historically given parameters for whom they believe should buy assets divested as part of a merger, but often leaves it to the companies themselves to strike an appropriate deal.