Fox News has confirmed that Senate Republicans told Democrats that they will formally filibuster the nomination of Chuck Hagel as Secretary of Defense.

Hagel's nomination was approved Tuesday

by the Armed Services Committee in a close vote, and he is awaiting a vote by the full Senate. The filibuster would block the up-or-down vote from taking place. Democrats don't have the 60 votes needed to break the filibuster.

The up-or-down vote was supposed to take place tomorrow.

Senate Majority Leader Harry Reid (D-Nev.) calls it "shocking that my Republican colleagues would leave the nation without a fully empowered Secretary of Defense during all the things we have going on in the world, including a war."