Former Vice President Joe Biden went on the offense Saturday over President Trump’s July phone call with the president of Ukraine, in which Trump reportedly urged the leader to investigate Biden’s son’s dealings in the country -- with Biden backing calls for a House investigation and for the White House to release the transcript of the call.

“Trump’s doing this because he knows I’ll beat him like a drum, and he’s using the abuse of power and every element of the presidency to try to do something to smear me,” he told reporters in Iowa.

NEW DETAILS REPORTED ON TRUMP-UKRAINE CALL AS DEMS CLASH WITH WHITE HOUSE ON COMPLAINT

The Wall Street Journal reported Friday that, in a July phone call, Trump repeatedly asked Ukrainian President Volodymyr Zelensky to work with Trump lawyer Rudy Giuliani on a probe into Hunter Biden.

Joe Biden, now a Democratic presidential candidate, has faced scrutiny for months over his role as VP in pressuring the country to fire its top prosecutor while he was leading a corruption investigation into a natural gas company that had ties to Hunter. Giuliani has suggested that Biden, as vice president, worked to protect the company from investigation.

On Saturday, Biden said that he had never spoken to Hunter about his business dealings in Ukraine, and backed calls for the House to investigate -- as well as suggesting it could begin a path to impeachment.

“Depending on what the House finds, he could be impeached but I’m not making that judgment now,” he said. “The House should investigate it, this appears to be an overwhelming abuse of power.”

He went on to call Trump a “serial abuser.”

“He abuses power everywhere he can and if he sees any threat to staying in power, he’ll do whatever he has to do -- but this crosses the line,” he said.

CONTROVERSY OVER TRUMP PHONE CALL CENTERS ON UKRAINE, AS PRESIDENT DECRIES 'PARTISAN' COMPLAINT

Biden’s remarks came just hours after Trump dismissed the controversy as a “Ukraine Witch Hunt” being stoked by the Democratic Party and the “fake news media,” and said that the real scandal was to do with Biden’s interactions in the country.

“The Fake News Media and their partner, the Democrat Party, want to stay as far away as possible from the Joe Biden demand that the Ukrainian Government fire a prosecutor who was investigating his son, or they won’t get a very large amount of U.S. money, so they fabricate a.story about me and a perfectly fine and routine conversation I had with the new President of the Ukraine,” he tweeted.

“Nothing was said that was in any way wrong, but Biden’s demand, on the other hand, was a complete and total disaster. The Fake News knows this but doesn’t want to report!”

What initially touched off the controversy is a secret whistleblower complaint that the director of national intelligence has kept from Congress, reportedly involving a "promise" Trump made to an unnamed foreign leader.

Trump dismissed the story as “ridiculous" and a "partisan hack job" from the Oval Office on Friday and said his calls with foreign leaders are “always appropriate.”

The whistleblower complaint led House Intelligence Committee Adam Schiff, D-Calif., and other Democrats to call for an investigation and for the administration hand over the complaint as well as a transcript of the call -- even as acting Director of National Intelligence Joseph Maguire declined to share details with lawmakers.

Maguire is expected to testify publicly about the whistleblower complaint on Sept. 26. after being subpoenaed by the House intelligence committee. Schiff had accused Maguire of withholding a whistleblower complaint from Congress and questioned whether he had been directed to do so by the White House or the attorney general.

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On Saturday Trump said that the media was turning the story into one about him, as they are trying to “protect” the Democratic frontrunner.

“Now that the Democrats and the Fake News Media have gone ‘bust’ on every other of their Witch Hunt schemes, they are trying to start one just as ridiculous as the others, call it the Ukraine Witch Hunt, while at the same time trying to protect Sleepy Joe Biden,” he tweeted. “Will fail again!”

Fox News' Alex Pappas and The Associated Press contributed to this report.