CEDAR RAPIDS, IOWA – Former Vice President Joe Biden on Friday accused President Trump of "abhorrent" behavior amid news reports that the president pressured Ukraine's president to launch an investigation into Hunter Biden's business dealings in the country.

Biden's comments come in the wake of multiple news reports that a whistleblower from the intelligence community filed a complaint with the inspector general overseeing the community concerning a phone call Trump made with a foreign leader.

Lawmakers are separately investigating whether Trump pushed for Ukraine President Volodymyr Zelensky to probe Biden's family's dealings in his country.

"If these reports are true, then there is truly no bottom to President Trump’s willingness to abuse his power and abase our country," Biden said in a statement Friday evening. "This behavior is particularly abhorrent because it exploits the foreign policy of our country and undermines our national security for political purposes. It means that he used the power and resources of the United States to pressure a sovereign nation — a partner that is still under direct assault from Russia — pushing Ukraine to subvert the rule of law in the express hope of extracting a political favor."

Asked earlier by reporters after a campaign event in Cedar Rapids, Iowa, about reports that Trump wanted Biden's son Hunter to be investigated by the Ukrainian government, Biden offered only a brief comment defending his son.

“Whoa, whoa, whoa ... wait a second. Not one single credible outlet has given credibility to these assertions. Not one single one," Biden said as he left a nature center where he had spoken at a town hall on climate issues. "So I have no comment other than the president should start to be president.”

Biden added in an interview with the political blog Iowa Starting Line that he found it "concerning to me that a president would do something like that."

“It’s totally inappropriate for a president to try to get a foreign leader to say something that is untrue about any political opponent,” Biden said in the interview. “I’ve never heard of it before. I’ve never heard of it before. But I think that Congress is looking into it, and I think they should.”

The president's personal attorney Rudy Giuliani has previously raised questions that Biden, as vice president, had pushed for the ouster of former Ukrainian prosecutor general Viktor Shokin, who had investigated a private Ukrainian gas company, Burisma Group. Hunter Biden was a board member of Burisma.

But Ukraine's current prosecutor, Yuriy Lutsenko, told Bloomberg News Service in May that he had no evidence of wrongdoing by Biden or his son.

“Hunter Biden did not violate any Ukrainian laws — at least as of now, we do not see any wrongdoing,” Lutsenko told Bloomberg. “A company can pay however much it wants to its board.”

The Wall Street Journal reported Friday that Trump in a July phone call repeatedly pressured Zelensky to investigate Hunter Biden and work with his personal attorney, Giuliani, on the matter.

"At minimum, Donald Trump should immediately release the transcript of the call in question, so that the American people can judge for themselves, and direct the Office of the Director of National Intelligence to stop stonewalling and release the whistleblower notification to the Congress," Biden said.

Biden has previously said he wanted Shokin out as prosecutor general because he wasn’t doing enough to investigate corruption. The former vice president in March 2016 called on Ukraine’s Parliament to dismiss Shokin, or the United States would withhold $1 billion in loan guarantees, according to the New York Times. Shokin was voted out by parliament, but no evidence showing Biden intentionally tried to benefit his son has surfaced.

Still, Trump in a May interview on Fox News suggested Biden engaged in a quid pro quo with Ukraine's government.

“Look at Joe Biden … he calls them [Ukrainian government leaders] and says, 'Don’t you dare prosecute,'" Trump said in the interview. "'If you don’t fire this prosecutor’ — the prosecutor was after his son — then he said, ‘If you fire the prosecutor, you’ll be OK. And if you don’t fire the prosecutor, we’re not giving you $2 billion in loan guarantees,’ or whatever he was supposed to give. Can you imagine if I did that?"

Earlier Friday, Trump called reports of the whistleblower complaint against him a “ridiculous story” and said his communications with other leaders were “at the highest level always appropriate.” Asked by reporters Friday if he had raised questions about Biden's dealings in the Ukraine during a July phone call with Zelensky, Trump replied, “Someone ought to look into Joe Biden.”

He said it "doesn't matter" if he asked the government of Ukraine to investigate Joe Biden and that it should be done anyway.

Trump again attacked Biden in a Tweet on Saturday morning. He said his conversation with Zelensky was "perfectly fine and routine." He added that, "nothing was said that was in any way wrong, but Biden’s demand, on the other hand, was a complete and total disaster."

Democratic presidential contender Kamala Harris came to Biden's defense and hammered Trump over reports that he sought foreign help to go after a political rival.

“He has openly invited interference," the California senator told reporters prior to a speech in Waterloo, Iowa. "And now we have information that suggests that, again, he has engaged in that kind of behavior. What he fails to understand is that he is the president of the United States, and that the office of the president of the United States is the people’s office — not his office. And he may be afraid of a candidate in this election."

"Well then win on merit, but leave Joe Biden alone in terms of being in cahoots and collaborating with a foreign government to attack our democracy," Harris said. "That’s what this is about. It's really basic. Donald Trump appears to be collaborating with foreign governments to attack America’s democracy.”

Sen. Cory Booker, another Democratic presidential contender, called Trump's reported attempts to pressure the Ukrainian president "sober and serious stuff."

"It should be, in many ways, rocking Washington right now,” Booker said on the sidelines of an LGBTQ campaign forum in Cedar Rapids Friday. “This is not a partisan issue. This is the president engaging in behavior that amounts to, at the very least, serious misconduct.”

Sen. Elizabeth Warren wrote on Twitter that Congress' failure to impeach Trump following the release earlier this year of the Mueller report made it “complicit in Trump’s latest attempt to solicit foreign interference to aid him in US elections.”

“Do your constitutional duty and impeach the president,” Warren added. “A president is sitting in the Oval Office, right now, who continues to commit crimes. He continues because he knows his Justice Department won't act and believes Congress won’t either. Today’s news confirmed he thinks he’s above the law. If we do nothing, he’ll be right.”