WASHINGTON — Democrats on the US House Judiciary Committee on Thursday prepared a subpoena to compel acting Attorney General Matthew Whitaker to testify on Friday, prompting Whitaker to say he will not appear unless the subpoena threat is lifted.

The committee's Democrats wants to question Whitaker about his oversight of Special Counsel Robert Mueller's investigation of Russian interference in the 2016 election and his communications with the White House related to the probe and the firing of former Attorney General Jeff Sessions.

But Whitaker, who President Donald Trump chose to head the Justice Department after firing Sessions in November, said the possibility of a subpoena showed the committee's "true intention is ... create a public spectacle."

Shortly before Whitaker's threat to withdraw from the hearing, the House Judiciary Committee had voted 23-13 along party lines to have a subpoena ready in case Whitaker fails to show up or refuses to answer questions.

House Judiciary Committee Chairman Jerrold Nadler said the vote only authorized a subpoena, but that one would not be issued as long as Whitaker appeared at the hearing and cooperated.

A subpoena would compel Whitaker to testify. If he still declined, Democrats could potentially take steps to have him held in contempt of Congress.

Whitaker, in a statement, said he would only show up if Democrats committed not to issue a subpoena.

Whitaker has faced criticism since Trump appointed him. Prior to joining the Justice Department, Whitaker made multiple negative comments about Mueller’s investigation into whether Trump’s campaign may have colluded with Russia.

He also has declined to recuse himself from overseeing the investigation after career ethics officials at the department urged him to step aside to avoid the appearance of a conflict.

Trump has denied collusion with Russia and has called Mueller's probe a witch hunt.

Nadler has warned Whitaker that he should not try to dodge questions by asserting the answers could involve matters subject to executive privilege, and provided Whitaker in advance with a list of questions he can expect on Friday.

Sessions often refused to discuss any of his communications with the White House, even if the White House had not invoked executive privilege.

Nadler also has tussled with the Justice Department over the scheduling for Whitaker's testimony.

On Thursday, Nadler claimed some Justice Department officials may have counseled Whitaker not to attend Friday's hearing, although he still believes Whitaker will show up.

Republicans blasted Democrats for using the possibility of a subpoena to hang over Whitaker's head after he voluntarily agreed to appear.

"This subpoena is nothing short of political theater, choreographed by the chairman and starring the acting attorney general as some mythological protector of secrets," said Doug Collins, the most senior Republican on the Judiciary Committee.

Representative Jim Jordan, a member of the conservative Freedom Caucus, also blasted the move. "This is ridiculous. The guy is coming," he said. — Reuters