Trump refuses to explain what he wanted Ukraine's president to do about the Bidens

He also called the whistleblower statement alleging wrongdoing "vicious."

President Donald Trump on Wednesday lashed out at Democrats and their impeachment probe but repeatedly refused to answer a question at the heart of the investigation: On that July 25 phone call, what did he want Ukraine's president to do about Vice President Joe Biden and his son, Hunter?

Democrats claim he wanted to get political "dirt" on the Bidens.

But at an often-angry afternoon news conference with Finland's president, after Reuters' reporter Jeff Mason asked that question, Trump dodged, first criticizing European countries for not providing more aid to Ukraine and then going on a lengthy attack on the impeachment probe as a "hoax."

"The question, sir, was what did you want President Zelensky to do about Vice President Biden and his son Hunter?" Mason then asked.

"Are you talking to me?" Trump asked.

"Yes. It's just a follow-up of what I just asked you, sir," Mason responded.

"Listen, are you ready? We have the president of Finland. Ask him a question," Trump stated.

"I have one for him. I wanted to follow-up on the one that I asked you," Mason said.

"Did you hear me? Did you hear me?" Trump shot back. "Ask him a question. I've given you a long answer, ask this gentleman a question. Don't be rude. I've answered everything. It's a whole hoax. And you know who's playing into this hoax? People like you and the fake news media that we have in this country. And I say in many cases, the corrupt media," Trump said.

Asked by another reporter whether he'll cooperate with subpoenas Democrats on Thursday threatened to send to the White House for Ukraine-related documents, Trump answered, "Well, I always cooperate. This is a hoax. This is the greatest hoax, this is just a continuation of what's been playing out ... for the last, since my election I would say... To impeach a president over a fraud that was committed by other people that wanted to win an election in 2020, which they won't, is incredible. This is the greatest hoax."

He continued his attack on the Democrat leading the impeachment probe, House Intelligence Committee Chairman Adam Schiff, calling what he's said "criminal." And he said House Speaker Nancy Pelosi, who told ABC Chief Anchor George Stephanopoulos in an exclusive interview that Trump was "scared" of the impeachment inquiry, "hands out subpoenas like cookies."

Trump then attacked the whistleblower who has alleged wrongdoing on phone call, saying "you look at the whistle-blower statement, and it's vicious. Vicious. And that whistle-blower, there's no question in my mind that some bad things have gone on and I think we'll get to the bottom of it."

"This country has to find out who that person was, because that person’s a spy, in my opinion,” Trump said speaking to reporters at an Oval Office photo-op with Finland's president.

At the same time, Trump said he believes that the identity of whistleblowers should be protected, but only in some cases.

"I think a whistleblower should be protected if the whistleblower’s legitimate," he said, making clear that he does not believe the whistleblower in this case deserves those protections.

Trump has pushed back dramatically against the Democrats' impeachment inquiry, claiming a "coup" was "taking place" to take away the people's power.

"As I learn more and more each day, I am coming to the conclusion that what is taking place is not an impeachment, it is a COUP, intended to take away the Power of the... People, their VOTE, their Freedoms, their Second Amendment, Religion, Military, Border Wall, and their God-given rights as a Citizen of The United States of America!" the president tweeted Tuesday evening.

As Democrats investigate Trump's dealings with Ukraine, the president has repeatedly attacked the whistleblower whose complaint sparked their impeachment inquiry.

On Monday, Trump told reporters in the Oval Office that "we're trying to find out about a whistleblower." He claimed the whistleblower reported "things that were incorrect" about his phone call with Ukrainian President Volodymyr Zelenskiy, even though the complaint largely tracked with the contents of a rough transcript subsequently released by the White House.

In other tweets Tuesday he said, "So if the so-called “Whistleblower” has all second hand information, and almost everything he has said about my “perfect” call with the Ukrainian President is wrong (much to the embarrassment of Pelosi & Schiff), why aren’t we entitled to interview & learn everything about .... the Whistleblower, and also the person who gave all of the false information to him."

The president has also repeatedly claimed the whistleblower was a political partisan. While the intelligence community's inspector general did find that there were some indications the whistleblower had "arguable political bias... in favor of a rival candidate," the inspector general also said that the revelation did not change his assessment that the complaint appeared credible.

As Trump keeps hitting the whistleblower -- who enjoys legal protection under whistleblower laws and wants to remain anonymous -- Sen. Chuck Grassley, R-Iowa, defended the person, whose identity has not been made public.

"No one should be making judgments or pronouncements without hearing from the whistleblower first and carefully following up on the facts. Uninformed speculation wielded by politicians or media commentators as a partisan weapon is counterproductive and doesn’t serve the country," Grassley said in a statement.

Trump's rhetoric has rapidly escalated as Democrats in the House push forward with their inquiry.

On Sunday, he tweeted paraphrased Pastor Robert Jeffress, a conservative commentator speaking on "Fox and Friends," saying, "If the Democrats are successful in removing the President from office (which they will never be), it will cause a Civil War like fracture in this Nation from which our Country will never heal."

His invocation of a possible "Civil War" drew fierce blowback from Rep. Adam Kinzinger, R-Ill., who tweeted: "I have visited nations ravaged by civil war. @realDonaldTrump I have never imagined such a quote to be repeated by a President. This is beyond repugnant."

It was not the first time Trump connected impeachment with political conflict. In December, he told Reuters "the people would revolt" if he were impeached.