WASHINGTON, United States — US House Speaker Nancy Pelosi and Senate Majority Leader Mitch McConnell sparred on Monday over the ground rules for President Donald Trump’s trial in the Senate on charges of abuse of power and obstruction of Congress.

Pelosi, the speaker of the Democratic-controlled House of Representatives, said she is not yet ready to name her team for Trump’s trial in the Republican-majority Senate.

“The House cannot choose our impeachment managers until we know what sort of trial the Senate will conduct,” Pelosi said on Twitter.

House managers will prosecute the case against Trump in the Senate in a trial expected to begin in January. Trump’s Republicans have a 53-47 seat edge in the chamber.

Pelosi has not yet sent the impeachment articles passed by the House last week over to the Senate amid a standoff with McConnell over the form the trial will take.

Democrats have been pushing for four current and former White House aides with direct knowledge of Trump’s Ukraine dealings to testify in the Senate.

Trump blocked all four from testifying in the House. Democrats believe their appearances would bolster the case for conviction in the Senate, where a two-thirds majority is needed to remove the president from office.

“President Trump blocked his own witnesses and documents from the House, and from the American people, on phony complaints about the House process,” Pelosi said. “What is his excuse now?”

McConnell, speaking on the Fox & Friends television show on Monday, said Pelosi “apparently believes that she can tell us how to run the trial”.

“We haven’t ruled out witnesses,” McConnell said, adding that he wanted to apply the same rules as in the impeachment trial of President Bill Clinton.

“You listen to the opening arguments, you have a written question period, and at that point in the Clinton trial, we had a decision about which witnesses to call,” he said.

“What was good enough for President Clinton is good enough for President Trump,” the Republican senator from Kentucky said.

McConnell chided Pelosi for not sending the impeachment articles over to the Senate yet.

“The papers have to be physically brought over to the Senate, and we can’t go forward until the speaker does that,” he said. “She’s apparently trying to tell us how to run the trial.”

“You know, I’m not anxious to have this trial,” McConnell added. “So if she wants to hold all the papers, go right ahead.”

“Sooner or later, I’m assuming she’s going to send them over,” he said. “It seems to me a rather absurd position to say, after you’ve impeached the president, you won’t send the papers over to the Senate for the impeachment trial mandated by the Constitution.”

Trump, who is on vacation in Florida, lashed out at Pelosi.

“Pelosi gives us the most unfair trial in the history of the US Congress, and now she is crying for fairness in the Senate, and breaking all rules while doing so,” he said on Twitter.

The House voted along party lines last week to impeach Trump for abuse of power for pressuring Ukraine’s president to investigate his potential 2020 election opponent, Democrat Joe Biden.

Trump is accused of withholding military aid to Ukraine to push Kiev to investigate Biden.

According to an internal email published over the weekend, a US budget official told the Pentagon to “hold off” on military aid to Kiev 90 minutes after a controversial July 25 phone call between Trump and his Ukrainian counterpart Volodymyr Zelensky.

Lawmakers also impeached Trump for obstructing the congressional probe into his Ukraine dealings.