The US House of Representatives will hold its first formal vote on Thursday on the impeachment inquiry into President Donald Trump, a senior aide said, as Democrats forge ahead with a process that includes upcoming public hearings.
The measure will "lay out the next steps for the inquiry," a senior Democratic aide told AFP on Monday after House Speaker Nancy Pelosi informed fellow Democrats about the plan.
The effort appears aimed at pushing back against Trump and Republicans who have argued an impeachment proceeding lacks authorisation without a full floor vote.
"This week, we will bring a resolution to the floor that affirms the ongoing, existing investigation that is currently being conducted by our committees as part of this impeachment inquiry," Pelosi said in a letter to her caucus.
The measure is likely to pass in the Democratic-controlled House given that 228 Democrats, out of a total 435 House members, are on record supporting impeachment or an impeachment inquiry.
The measure "establishes the procedure for hearings that are open to the American people, authorises the disclosure of deposition transcripts (and) outlines procedures to transfer evidence to the Judiciary Committee as it considers potential articles of impeachment," she added.
To date, all witness testimony in the month-long inquiry has occurred behind closed doors, leading Republicans to slam the process as a secretive and illegitimate.
'Eliminate any doubt'
The resolution, Pelosi said, also "sets forth due process rights for the President and his Counsel" -- steps that Republicans had repeatedly stressed were being ignored by the House's majority party.
"We are taking this step to eliminate any doubt as to whether the Trump Administration may withhold documents, prevent witness testimony, disregard duly authorised subpoenas, or continue obstructing the House of Representatives," she added.
Pelosi, Trump's chief adversary in Congress, made her move as the impeachment showdown took an urgent new tone in Washington as a key witness defied a US House subpoena to testify.
The White House has sought to block the appearance by ex-deputy national security advisor Charles Kupperman, who last week took the rare step of filing a lawsuit urging a court to rule on whether he should obey the commands of the executive branch or the legal imperatives of Congress.
Democrats are keen to hear from Kupperman, as he reportedly was on the July 25 telephone call between Trump and his Ukrainian counterpart in which the US leader pushed Kiev to investigate his political opponents.
That request by Trump, and accusations he conditioned nearly $400 million in military aid to Ukraine on the political favor, form the basis of the impeachment inquiry that began five weeks ago and now threatens his presidency.
The House Rules Committee will debate and hold a preliminary vote on the impeachment inquiry "transparency" measure at 3:00 pm (1900 GMT) Wednesday, the panel's chairman Jim McGovern said.
Should it clear the committee, it heads to the floor for a full vote the following day.