The White House says Chuck Hagel has already given lawmakers exhaustive information but will continue to disclose more to the Senate panel considering his nomination.
A Senate committee postponed a vote on the former Nebraska senator, putting in limbo his nomination to be Obama's second-term defense secretary. Republicans said they needed more information about Hagel's paid speeches and business dealings.
White House spokesman Jay Carney says Hagel has turned over all available speech transcripts, but that some of his speeches were never transcribed. He says it's vital that the Pentagon position be filled and is urging the Senate to approve Hagel quickly.
Republicans in a letter had complained Hagel didn't sufficiently answer questions, including inquiries about more than $5,000 in compensation he received over the past five years.
Nebraska Republican Sen. Deb Fischer will vote against Hagel. Fischer wrote an op-ed published Thursday in the Omaha World-Herald. She casts Hagel's views as out of the mainstream, a point she argued during his confirmation hearing last week. She also says Hagel gave "confusing and contradictory" testimony before the Senate Armed Services Committee.
Fischer's opposition was widely expected as Hagel endorsed her Democratic rival, former Sen. Bob Kerrey, in the November election.
Nebraska's other Republican senator, Mike Johanns, has said he supports Hagel for the job.