Republican Senators have the necessary 41 votes to block the confirmation of Chuck Hagel from coming to a vote this week, and will be able to stage a filibuster, according to an interview given by Sen. David Vitter (R-LA) to Breitbart News editor Larry O'Connor on Washington, DC-area WMAL radio this morning.

"The cloture vote is gonna be very close. It's gonna be today or tomorrow. We may very well defeat this first cloture vote," Vitter said.

ABC News' Jonathan Karl confirmed that Democrats do not yet have the votes to ensure that Hagel will be confirmed, as of Thursday morning:

It now looks like Democrats don’t have the votes to get Hagel confirmed, at least not yet.

That’s because Republicans are determined to block a straight up-or-down vote--at least for now--until Hagel turns over more information on his financial disclosure form and the Obama administration answers more questions about last year’s attack on the U.S. Consulate in Benghazi, Libya.

Vitter noted that delaying the confirmation vote would give the Senate more time to consider Hagel's record, including new information that is coming out "every day" about his background.

Earlier this morning, Breitbart News reported further evidence that a speech Hagel gave to the Arab-American Anti-Discrimination Committee, and which he had not disclosed to the Senate, was likely a formal address, even if it was an extemporaneous one. 

Hagel and the Obama administration have maintained that the ADC speech and many others like it were "informal" and therefore there was no obligation to report them.

UPDATE: Fox News Channel confirms: "Senior Republican sources [are] telling Democrats they intend to mount a full-scale filibuster of the Chuck Hagel nomination and will block his nomination from receiving an up or down vote."