The House will delay sending the articles of impeachment it approved to the Senate until rules are established for the trial of President Donald Trump, Speaker Nancy Pelosi said Wednesday night.

Pelosi, D-Calif., excoriated Senate Majority Leader Mitch McConnell, R-Ky., for saying he would coordinate with the White House counsel during the coming trial, which she likened to the foreman of a jury being in "cahoots" with the defendant's attorney.

Pelosi said the House also had yet to settle on its impeachment managers for the trial.

"We're not sending [the articles] tonight because it's difficult to determine who the managers would be until we see the arena in which we will be participating," said Pelosi, who was joined by the leaders of the six committees that led the House impeachment inquiry.

"So far, we haven't seen anything that looks fair to us, so hopefully it will be fairer, and when we see what that is, we'll send our managers," she said.

The reaction at the White House to a possible delay was one of incredulity.

A source familiar with the administration's reaction asked: "How can these people be taken seriously?"

The source, who spoke on the condition of anonymity, described the announcement as a continuation of "the absolute abandoning of any reliable precedent," characterizing Pelosi as simply "continuing to play games."

Earlier, McConnell said he hadn't coordinated with Pelosi on when the articles would be delivered.

"You'd have to ask her when she's going to send them," he said.

Senate Minority Leader Chuck Schumer, D-N.Y., pointed out that "at the start of a trial in the Senate, all senators will swear an oath to render impartial justice."

"The American people deserve that the Senate conduct a full and fair trial," Schumer said.

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Pelosi, who called the day historic and sad, also congratulated the Democratic caucus, saying Democrats did not whip votes or discuss how they were voting.

"I could not be prouder or more inspired than by the moral courage of the House Democrats," she said.

She also honored the late Rep. Elijah Cummings, D-Md., who as chairman of the Committee on Oversight and Reform was responsible for conducting various investigations of the Trump administration.

"We did all we could, Elijah," she said. "We passed the two articles of impeachment. The president is impeached."