Republican lawmakers say the White House may have tried to push through a company's proposed wireless network despite objections from the military that the project could disrupt vital satellite navigation systems.

Lawmakers this week raised fresh questions about the proposed network by Virginia-based Lightsquared, a firm backed by billionaire Philip Falcone, a prominent donor to Obama's Democratic party.

At a hearing Thursday of the House of Representatives strategic forces subcommittee, the Republican chairman, Michael Turner, said he would request that the House Oversight Committee investigate whether the company received special treatment from the White House or federal regulators.

The hearing came after a report in the Daily Beast website alleged the White House pressed the head of US Air Force space command, General William Shelton, to downplay his concerns and alter his testimony to lawmakers.

President Barack Obama's administration denies the allegations, and Lightsquared has rejected charges it is getting special favors.

Republican staff members of the committee alleged the Air Force general told lawmakers that Obama administration officials lobbied him to express support in his testimony for the Lightsquare proposal, the Washington Post reported Friday.

At Thursday's hearing, Shelton said the proposed wireless broadband network by Lightsquared would interfere with the Global Positioning System (GPS) relied on by the military and private industry.

Tests with Defense Department experts, civilian agencies and others "indicate the LightSquared terrestrial network operating in the originally proposed manner poses significant challenges for almost all GPS users," Shelton told the committee.

The general's spokeswoman insisted Friday that Shelton had not watered down his testimony due to alleged White House pressure. "General Shelton's testimony was his own supported by and focused purely on documented test results," Colonel Kathleen Cook told AFP.

The company originally planned to provide only satellite phones on its network, but the Federal Communications Commission issued a waiver to the firm in January allowing LightSquared to offer terrestrial-based wireless service to companies.

The Defense Department has raised concerns about interference with GPS users previously, and the FCC has promised not to allow the firm to begin operating until more testing is carried out to ensure there is no disruption to satellite navigation users.

The head of the FCC declined to appear before the committee on Thursday, which the chairman, Turner, called an "affront" to the panel.