The Senate Intelligence Committee is set to hear today from FBI Director Robert Mueller on last month’s joint House-Senate report on the Sept. 11, 2001, terrorist attacks, even as momentum to declassify still-secret portions of the report dealing with Saudi Arabia appears to be waning.

While there is still support among a large block of Senators to release the 28 pages of the report that are still classified, top Bush administration officials have been vehemently opposed. The redacted pages allegedly spell out evidence of Saudi ties to the Sept. 11 hijackers. The White House has twice denied Congressional requests to declassify that portion of the 900-page overall document.

Prior to the recess, Sens. Sam Brownback (R-Kan.) and Charles Schumer (D-N.Y.) circulated a letter urging release of the redacted pages. So far, 46 Senators have signed onto the letter, which urges the White House to engage in “responsible redaction,” although Brownback is the only Republican to do so.

Two other Republicans, Sens. Richard Shelby (Ala.) and Olympia Snowe (Maine), have indicated that they would support the Brownback-Schumer proposal.

But Snowe took a softer line in an interview Wednesday, and Senate Intelligence Chairman Pat Roberts (R-Kan.) said no member of his panel has offered a resolution to overrule the White House — a cumbersome process that has yet to be tested.

“I think this is a chance to have an ongoing discussion,” Snowe said of today’s appearance by a top Bush official before the intelligence panel.

Roberts has been particularly vocal in his opposition to any attempt to declassify the still withheld 28 pages, arguing that to do so would jeopardize sources and methods used by CIA and FBI intelligence experts, as well as potentially compromise ongoing investigations into the Sept. 11 attacks.

But Sen. Bob Graham (D-Fla.), who chaired the Senate Intelligence Committee during the joint House-Senate hearings into the attacks on the World Trade Center and Pentagon, has blasted the White House for its refusal to budge. Graham called it part of “a pattern of delay and excessive use of national security standards to deny the people the knowledge of their vulnerability.”

Sen. Jay Rockefeller (D-W.Va.), the ranking member on the Intelligence panel, has not signed onto the Brownback-Schumer letter.

But other Senate Democrats, led by Sen. Carl Levin (Mich.), have joined with groups representing families of victims of the attacks in urging the Bush administration to release the classified pages.