White House counselor Kellyanne ConwayKellyanne Elizabeth ConwayTrump allies assail impeachment on process while House Democrats promise open hearings soon Sunday shows - Next impeachment phase dominates Conway: 'I don't know' if military aid was withheld from Ukraine over request for Biden investigation MORE said Wednesday that acting chief of staff Mick MulvaneyJohn (Mick) Michael MulvaneyGraham predicts controversial Trump court picks will clear panel House Democrats ask Mulvaney to testify in impeachment inquiry Overnight Defense: Dems release first impeachment probe transcripts | White House officials refuse to testify Monday | US, Iran mark 40th anniversary of hostage crisis MORE is not expected to appear for testimony Friday in connection with the House impeachment inquiry.

“I’m told no,” Conway told reporters at the White House when asked if Mulvaney would testify later this week as requested by House lawmakers.

Three House committees on Tuesday sent a letter to Mulvaney asking him to appear for a deposition on Friday. If the acting White House chief of staff does not appear, House Democrats could subpoena him.

Several current and former White House officials have defied subpoenas in the probe, citing immunity from compelled congressional testimony.

Conway on Wednesday hammered the impeachment inquiry process, a key criticism of the White House. She argued that the closed-door hearings should have been public from the start and that House Democrats cannot rectify the issue by holding public hearings in the coming weeks, as they agreed to do in a House floor vote last week.

“The hearings should have been public from the beginning. They can’t cure a bad process,” Conway said. “The process has been ill-conceived from the beginning.”

Conway also suggested House Democrats had launched the inquiry in search of an offense by President TrumpDonald John TrumpThe Hill Interview: DNC chair calls Latinos 'imperative' to winning in battleground states Democrats give Warren's 'Medicare for All' plan the cold shoulder Senate Republicans struggle to coalesce behind an impeachment strategy MORE.

“Why would we try to be complicit in an impeachment inquiry when we don’t know what it’s about?” Conway asked.

Conway said she didn’t know if she would be called to testify but said she wasn’t worried about it.

The House impeachment inquiry is focused on a July 25 call during which Trump asked Ukraine’s president to look into former Vice President Joe BidenJoe BidenDemocrats give Warren's 'Medicare for All' plan the cold shoulder Senate Republicans struggle to coalesce behind an impeachment strategy Sanders team accuses media of ignoring 'surge' in polls MORE and his son Hunter’s business dealings in Ukraine.

Democrats are investigating, among other things, whether the Trump administration held up U.S. military aid to Ukraine in order to exert pressure on Ukraine to launch investigations sought by Trump.

Some impeachment witnesses have described what amounts to a quid pro quo related to the aid, but Trump and his aides have insisted there was no quid pro quo in his interactions with Ukraine and that he did nothing wrong.

Mulvaney, who is also the director of the Office of Management and Budget, is viewed as a key witness for Democrats because of his involvement in decisions related to the $400 million in security aid to Ukraine that was eventually released.

At a press conference last month, Mulvaney indicated that aid was contingent in part on Ukraine pursuing an investigation related to the Democratic National Committee server. He later walked back his remarks by insisting that there was no quid pro quo and that the media had misconstrued his statements.