Only hours away from presumably sending President Donald Trump’s impeachment articles to the Senate, House Speaker Nancy Pelosi said senators who don’t allow new witness testimony during the trial “will pay a price.”

"It's about a fair trial," Pelosi told ABC's "This Week." "The senators who are thinking now about voting for witnesses or not, they will have to be accountable.

“Now the ball is in their court to either do that or pay a price.”

Last week, Pelosi said she would send over the two articles of impeachment this week, more than a month after House Democrats adopted them. Despite Democrats' professed sense of urgency in passing the articles, Pelosi had delayed sending the charges over, or name the trial's House managers, until Senate Majority Leader Mitch McConnell announces how the trial will proceed.

U.S. House Democrats have drafted two articles of impeachment against President Donald Trump. House leaders are charging the president with abuse of power and obstruction of Congress. They announced the articles of impeachment on Dec. 10, 2019. A full House impeachment vote could come before Christmas. If passed, the president would face a Senate trial in 2020, a presidential election year.

Senate Minority Leader Chuck Schumer (D-N.Y.) and other House Democrats have been demanding additional witnesses be called during a Trump trial, thus stalling any scheduling of a trial.

Now, that trial could begin this week, as Pelosi faced increasing pressure from within her own party last week to transmit the articles.

For his part, Trump has sent mixed signals regarding his impeachment via Twitter, alternately suggesting calling even more witnesses or advocating the Senate dismiss the charges entirely.

The president is also calling on Pelosi and House Intelligence Committee Chairman Adam Schiff (D-California) to testify.

Pelosi is reportedly meeting with Democratic leaders on Tuesday to discuss naming House impeachment managers and an exact date the articles will be transmitted to the House.

Trump faces charges that he abused power by pushing Ukraine to investigate Democratic rival Joe Biden and then obstructed Congress.

Senate Majority Leader Mitch McConnell has advocated for weeks that a Trump impeachment trial would follow the same model as Bill Clinton's in 1999.

President Bill Clinton was impeached on perjury and obstruction of Congress charges on Dec. 19, 1998. He was acquitted by the Senate on Feb. 12, 1999. Fourteen senators from that trial still remain in office. Here's how they voted. Susan Collins, R-Maine. Not guilty on both counts Michael D. Crapo, R-Idaho. Guilty on both counts Richard Durbin, D-Illinois. Not guilty on both counts Mike Enzi, R-Wyoming. Guilty on both counts Dianne Feinstein, D-California. Not guilty on both counts Charles Grassley, R-Iow

In the weeks since Trump was impeached, Democrats have focused on new evidence about Trump’s effort to pressure Ukraine to investigate his political rivals and they pushed the Senate to consider new testimony, including from former White House national security adviser John Bolton.

Republican allies led by McConnell are ready to deliver swift acquittal without new testimony.

McConnell is reluctant to enter a divisive Senate debate over witnesses that could split his party and prolong a trial that is already expected to consume weeks of floor time.

McConnell already has enough votes to defeat any Democratic notions of calling witnesses who did not testify during Trump's House impeachment hearings.

Republicans have the leverage, with a 53-47 Senate majority, as McConnell rebuffs the Democratic demands for testimony and documents. But Democrats are using the delay to sow public doubt about the fairness of the process as they try to peel off wavering GOP senators for the upcoming votes. It takes just 51 senators to set the rules.

The Associated Press contributed to this report.