Sen. John Rockefeller, a West Virginia Democrat, has placed a hold on the nomination of telecommunications lawyer Robert McDowell to fill the third Republican seat on the Federal Communications Commission, two sources familiar with the matter said on Monday.

McDowell would break a 2-2 deadlock at the agency, which regulates the telecommunications and media industry. With a majority, the FCC has been expected to launch a review that could lead to relaxing media ownership restrictions.

His nomination would require confirmation by the full Senate but any senator can put a so-called hold on a nomination for any reason. Traditionally, Senate leaders try to resolve the differences that prompted the action.

A spokesman for Rockefeller declined to confirm or deny the hold, but said the lawmaker did have concerns about properly accounting for the Universal Service Fund, which subsidizes communications services for low-income and rural areas and is overseen by the FCC.

The Universal Service Administrative Co., which runs the USF E-Rate program, had to freeze hundreds of millions of dollars in subsidies when it was discovered that the program did not comply with certain government accounting rules.

Congress has eased those rules on the program while it reviewed possible changes and the subsidies resumed.

“Senator Rockefeller is looking for the administration to give written confirmation that the Universal Service Fund accounting problem is fixed,” said Rockefeller spokesman Stuart Chapman.

The two sources, who spoke on condition of anonymity, declined to identify the reason for the Senate hold on McDowell’s nomination.

More than one senator can put a hold on a nominee.

McDowell, 42, has been a lawyer for Comptel, a trade association that represents telephone and Internet companies that compete against bigger carriers like AT&T Inc. and Verizon Communications.

McDowell would fill a seat that expires June 30, 2009. The FCC has been tied with two Republicans and two Democrats for much of the last year.