WASHINGTON (Reuters) - Senior executives at T-Mobile US Inc and Sprint Corp made the case to U.S. officials in Washington last week that they should approve a planned tie-up between the two wireless companies, arguing a combined firm would have incentives to “aggressively lower prices.”

FILE PHOTO: A smartphones with Sprint logo are seen in front of a screen projection of T-mobile logo, in this picture illustration taken April 30, 2018. REUTERS/Dado Ruvic/Illustration

T-Mobile US Chief Executive John Legere, Sprint executive chairman Marcelo Claure, T-Mobile US chief operating officer Michael Sievert, and other senior executives met with Federal Communications Commissioner Jessica Rosenworcel on Thursday, according to a federal filing on Monday.

In a presentation made public on Monday, the firms said they would “focus on taking share from Verizon and AT&T through lower prices.”

If completed, the $26 billion merger would create a carrier with 127 million customers that would be a formidable competitor to the No.1 and No.2 wireless players, Verizon Communications Inc and AT&T, respectively.

A group of eight Democratic senators and independent Senator Bernie Sanders in February urged the Justice Department and FCC to reject the deal, saying monthly bills for consumers could rise as much as 10 percent. Consumer advocates warn the deal will reduce the number of national wireless carriers to three from four.

Sources told Reuters last week that the Justice Department had concerns about the merger in its current structure.

A person briefed on the matter confirmed Legere met on Thursday with the head of the Justice Department’s antitrust division, Makan Delrahim, as the government’s review nears a conclusion. A decision is likely by early June, people briefed on the matter said.

The Justice Department declined comment.

T-Mobile has said the combined company would be better and faster at building 5G, the next generation of wireless, to compete with AT&T and Verizon.

In its presentation to Rosenworcel, T-Mobile cited Verizon’s decision to charge $10 extra per month for 5G service. “This won’t happen when new T-Mobile introduces 5G,” the presentation said.

The agreement to combine the carriers, struck in April 2018, was approved by both companies’ shareholders in October and has received national security clearance, but still needs approval from the Justice Department and FCC. A number of state attorneys general are also reviewing the deal.

To win support for the deal, T-Mobile had said it would not increase prices for three years and has pledged to use some spectrum for wireless broadband in rural areas. The firms say the combined entity would add 11,000 additional employees by 2024 compared to the standalone firms.