Lawmakers are seeking information about allegations that MCI (search) avoided millions of dollars in fees by disguising the origin and routing of long-distance calls.

Rep. Billy Tauzin, R-La., chairman of the House Energy and Commerce Committee, asked the Federal Communications Commission (search) to explain how it is investigating the matter. He wants the agency to turn over documents related to that probe within two weeks.

"A gross violation of regulations governing the origination and termination of long-distance calls undermines the basic telecommunications system of the United States," Tauzin wrote Wednesday in a letter to FCC Chairman Michael Powell. "If true, these allegations represent an unprecedented violation of FCC rules."

FCC spokesman Richard Diamond said the agency will "cooperate fully with the committee and share the results of our own investigation."

The company, formerly known as WorldCom, was brought down by an $11 billion accounting scandal. It adopted the name of its MCI long-distance division in a bid to clean up its image. A bankruptcy court is considering efforts by the company to emerge from Chapter 11 bankruptcy protection.

Federal prosecutors are investigating accusations by rival carriers and former MCI executives that the company defrauded other telephone companies of hundreds of millions of dollars.

The investigation centers on whether MCI masked long-distance calls as local calls and diverted others to Canada to avoid paying special-access fees to local carriers across the country.

MCI has said its competitors are trying to throw up roadblocks to its emergence from bankruptcy.

Tauzin said he was particularly troubled by allegations that through a line-item fee MCI "may have been charging consumers fees for intrastate access charges that MCI was, in fact, circumventing."

The letter to Powell also was signed by Rep. Fred Upton, R-Mich., chairman of the committee's telecommunications subcommittee, which oversees the FCC.