Former Nebraska senator Chuck Hagel (AP)

This post has been updated.

Senate Armed Services Committee Chairman Carl Levin (D-Mich.) has delayed a vote on Chuck Hagel's nomination as defense secretary as 26 Republican senators demand more information from the former Nebraska senator.

The senators want Hagel to disclose who funded his private speeches, as well as any foreign funders of organizations to which he has profitable ties, according to a letter given to the Post by GOP sources.

Foreign Policy reported Tuesday evening that Sens. James Inhofe (R-Okla.) and Jeff Sessions (R-Ala.) would not agree to a Senate Armed Services Committee vote without more information from the former Nebraska senator.