The communication appeared to be the final threat by Judiciary Committee Chairman Pat Leahy, D-Vt., before initiating contempt proceedings, The Hill reported.
In the ruling, Leahy said the White House claims of immunity and executive privilege were "overbroad, unsubstantiated and not legally valid," setting the stage for a constitutional showdown between the legislative and executive branches, the newspaper said. Such showdowns have been settled in the past by the judicial branch.
The Hill said Leahy's formal ruling means the full Senate Judiciary Committee could consider contempt citations against the White House as early as next Thursday.
If the full committee approves the citation, the crowded Senate calendar likely would keep it from reaching a vote before the December holiday recess, The Hill said.
The newspaper added Leahy's statement is the latest indication the Senate majority Democrats may be serious about the citations.
Deputy Political Director J. Scott Jennings.
Democrats want to investigate the firing of up to eight U.S. attorneys, allegedly for investigating Republicans, failing to investigate Democrats or other political reasons.