The Justice Department sued to block the $39 billion deal, arguing that it would violate antitrust laws by stifling competition in the wireless industry. AT&T has vowed to fight the lawsuit in court but has indicated it is willing to negotiate with the Justice Department to address the agency's concerns.
The FCC is still conducting its own review of the deal.
In a separate letter last week, Rep. Todd YoungTodd YoungSenators introduce new Iran sanctions GOP lawmakers renew push for ISIS war authorization A guide to the committees: Senate MORE (R-Alaska) requested information from the Justice Department about its decision to file the lawsuit.
"A modern wireless network is an essential part of the free market economy and this merger could potentially provide better coverage and higher quality service to America's urban and rural areas," he wrote.
He said he was willing to work with the wireless providers and regulators to reach a settlement.
The Justice Department responded earlier this month to a similar request from Energy and Commerce Republicans to explain its decision to block the merger. The agency summarized its complaint against AT&T but did not provide any additional information, citing a policy against discussing ongoing litigation.