Speaker of the House Nancy Pelosi, D-Calif., meets with reporters following escalation of tensions this week between the U.S. and Iran, Thursday, Jan. 9, 2020, on Capitol Hill in Washington.

WASHINGTON — House Speaker Nancy Pelosi said Thursday she will not rush to deliver two articles of impeachment against President Donald Trump to the Senate.

"I'll send them over when I'm ready. That may be soon," Pelosi told reporters, revealing no signs that she planned to end her 3-week-long effort to negotiate with the Republican-controlled chamber over the rules of Trump's impeachment trial.

Pelosi, D-Calif., faces mounting pressure not only from Republicans, but increasingly from fellow Democrats, to deliver the articles, which would then permit the Senate to begin preparations for a trial.

"I'm not withholding them indefinitely," Pelosi said.

Pelosi's decision to delay sending the articles is part of a strategy aimed at forcing concessions out of Senate Majority Leader Mitch McConnell, R-Ky., chief among them, the ability to call witnesses.

McConnell has so far said the question of witnesses should be shelved until partway into the trial itself, as was the case in the 1998 impeachment of former President Bill Clinton.

"We want to see what they're willing to do, and the manner in which they will do it," Pelosi said Thursday. "But we will not let them say, 'This is just like Clinton, fair is fair.' It is not."

The House voted on Dec. 18 to impeach Trump on two articles stemming from his monthslong campaign to pressure Ukraine into launching investigations into Joe Biden and other domestic political opponents. The pressure tactics allegedly included withholding congressionally approved military aid to Ukraine in its fight against Russia. Trump was impeached on charges that he abused the power of the presidency and obstructed Congress by prohibiting top administration officials from testifying about the Ukraine scheme.

Following the articles' passage, Pelosi said she planned to hold them until McConnell assured her he would conduct what Democrats called "a fair process."

Democrats have insisted that any trial of the president include testimony from witnesses, something in which Republicans have so far shown no interest.

But the effort has so far failed to produce results, and the Senate leader said this week he would move forward on Trump's impeachment trial without any Democratic support.

It's considered highly unlikely that two-thirds of the GOP-controlled Senate will vote to convict and remove Trump from office. No Senate Republicans have said they support impeaching Trump.