U.S. Senate Majority Leader Mitch McConnell said Tuesday the Senate trial on impeachment against President Donald Trump is likely to get underway on Jan. 21 as House Democrats prepare to approve a resolution needed to begin proceedings on Wednesday.

The Democrat-led House will vote Wednesday to designate impeachment managers and send articles of impeachment to the Senate for the trial on charges of abuse of power and obstruction of Congress, Speaker Nancy Pelosi said in a statement on Tuesday.

"The House will now proceed with a vote on transmitting the articles of impeachment and naming impeachment managers on Wednesday, January 15," Pelosi said. "The President and the Senators will be held accountable."

Senate Republicans would be engaging in a "cover-up" if members vote to dismiss the articles without hearing from witnesses, Pelosi said in the statement.

"The American people will fully understand the Senate's move to begin the trial without witnesses and documents as a pure political cover-up," Pelosi said. "Leader McConnell and the President are afraid of more facts coming to light."

McConnell told reporters on Capitol Hill that the Senate will deal with the question of witnesses once the trial gets underway, and noted the president and his legal team would also want to call witnesses of their own.

"We will be dealing with the witness issue at the appropriate time into the trial," McConnell said. "And I think it's certainly appropriate to point out that both sides would want to call witnesses that they wanted to hear from."

The House passed the impeachment articles in mid-December, making Trump only the third president to face a Senate trial in the U.S. history.