US President Donald Trump’s impeachment probe hit dangerous new territory on Tuesday with what a Democrat called “explosive” testimony, supporting allegations that he pressured Ukraine for dirt on a political opponent.

Earlier on Tuesday, Trump described his impeachment as a “lynching” and he managed once again to create a political firestorm around race while frustrating members of his party and drawing condemnation from lawmakers who hold his political fate in their hands.

“Given the history of our country, I would not compare this to a lynching,” Senate Majority Leader Mitch McConnell, R-Ky. told to media.

“That was an unfortunate choice of words”, McConnell added.

Democrats roundly criticized the president’s comment, with some contemplating a House vote to condemn his language.

Taking to Twitter, Trump tweeted that, “So some day, if a Democrat becomes President and the Republicans win the House, even by a tiny margin, they can impeach the President, without due process or fairness or any legal rights”.

So some day, if a Democrat becomes President and the Republicans win the House, even by a tiny margin, they can impeach the President, without due process or fairness or any legal rights. All Republicans must remember what they are witnessing here – a lynching. But we will WIN!

— Donald J. Trump (@realDonaldTrump) October 22, 2019

“All Republicans must remember what they are witnessing here – a lynching. But we will WIN!”, Trump posted.

While the president’s tweet created a distraction from the substance of the impeachment process, it did little to improve Trump’s standing as he faces the most significant legal and political threat to his presidency yet.

His impeachment looked ever more likely after the Democratic-led lower house of Congress questioned the acting US ambassador to Ukraine, Bill Taylor.

Taylor is seen as a crucial witness in the case against Trump, who is accused of abusing his power to push Ukraine to investigate one of his main 2020 election rivals, Democrat Joe Biden.

But Tuesday was the first time Trump merged his willingness to stoke the country’s racial tensions with his bombastic counter-impeachment messaging campaign.

Last week, President Trump said that witnesses had provided substantial support for allegations that Trump illegally tried to force Ukraine to investigate his political rival, Joe Biden.

While the White House and Trump’s personal lawyer Rudy Giuliani refused to turn over subpoenaed documents on the Ukraine affair to Congress, House Intelligence Committee Chairman Adam Schiff said five witnesses had backed up allegations of misuse of power that could underpin formal impeachment charges.

Two weeks ago, Trump had said that he would participate in a going impeachment enquiry against him led by the House Democrats “if the rules are fair”.

Trump’s remarks came right after a day White House issued a letter that notified the Democrats of an uncooperative stance of the administration in relation to their efforts to remove the President from office.

“You have designed and implemented your inquiry in a manner that violates fundamental fairness and constitutionally mandated due process,” White House Counsel Pat Cipollone wrote in the letter to House Speaker Nancy Pelosi, House Intelligence Committee Chairman Adam Schiff, Oversight and Reform Committee Chairman Elijah Cummings and Foreign Affairs Committee Chairman Eliot Engel.

“This letter is manifestly wrong, and is simply another unlawful attempt to hide the facts of the Trump Administration’s brazen efforts to pressure foreign powers to intervene in the 2020 elections,” Pelosi said in a statement.

Earlier this month, Ukraine’s former president had said that he discussed investments with President Donald Trump’s attorney, Rudy Giuliani, in 2017, but that he never discussed Ukrainian companies with any US official.

(With inputs from agency)