In so doing, the Michigan Democrat raised the specter of a House floor vote by Thanksgiving on contempt of Congress citations against chief of staff Joshua Bolten and former legal counsel Harriet Miers.
"I am writing one more time to seek to resolve this issue on a cooperative basis," Conyers said in a letter to White House counsel Fred Fielding.
Conyers wants testimony and documents from Bolten and Miers on whether the Justice Department's purge of nine federal prosecutors last winter was carried out at the White House's behest.
Also in Conyers' sights: Karl Rove, the architect of Mr. Bush's rise to the White House and a top political adviser who left last summer.
A contempt report had not been delivered to the House clerk Monday morning. If Fielding refuses to provide the information the Judiciary panel is demanding, the House could vote on the contempt citation before it recesses for Thanksgiving on Nov. 16.
Fielding has declared that the information Conyers seeks is off-limits to lawmakers under the doctrine of executive privilege.
Keeping the U.S. attorney controversy alive are several political and administrative developments, including the pending Senate vote on the confirmation of Michael Mukasey as attorney general. Unlike former Attorney General Alberto Gonzales, Mukasey during his confirmation hearings did not rule out prosecuting Miers and Bolten for contempt of Congress.
The committee was expected to file the contempt report with the clerk of the House later Monday, several Democratic officials said. If passed by the House, the contempt citation would be referred to the office of the U.S. attorney for the District of Columbia.
In what he said was his ninth letter to the White House on this issue, Conyers said he was trying one last time to reach an agreement on the release of the information.
The proposal included an initial release of communications between White House officials and others on the firings, according to Conyers' letter to Fielding. The White House would then make available for confidential staff review any remaining internal White House documents on the same subjects.
Finally, Miers, Rove and other, lower-ranking current and former White House officials would be interviewed along the lines of Fielding's previous offer of private testimony not under oath. Conyers insisted on a transcript of any such question-and-answer sessions, however. That's a condition that Fielding so far has rejected.
Conyers asked Monday that Fielding reply by end of the week. Congress goes on a two-week recess in mid-November.