Investigative journalist Peter Schweizer has called on the Senate to invite Hunter Biden to testify about his business dealings in China and Ukraine - both of which were linked to his father, former Vice President and 2020 presidential candidate Joe Biden.

"What I’ve called for simply is for the Senate to call former second son Hunter Biden to come and testify and people look into this," said Schweizer in an exclusive interview with The Hill. "We’re talking about large deals and large sums of money...it involves countries like China, which are America’s chief rival on the global stage."

1/ NEW: @peterschweizer calls for Hunter Biden to testify before the Senate and for investigations into whether the Chinese/Ukrainian governments were seeking to influence US policy when they inked big business deals with his company https://t.co/hyRK5xKIaH pic.twitter.com/2z6bFVty6S — Saagar Enjeti (@esaagar) May 14, 2019

The researcher provided an overview of Hunter Biden's alleged business dealings with Ukrainian energy company Burisma and the Chinese government in a recent New York Post op-ed that details payments of more than $3 million to Hunter Biden's company during a 14-month period when his father was the point person on Ukraine policy for the Obama administration. -The Hill

"In the case of the Ukraine, the very energy company that was paying Hunter Biden millions of dollars was under investigation in the Ukraine for corruption. Ukrainian officials have claimed that Joe Biden pressured them to suspend or end that investigation. That’s in fact what the Ukraine did," said Schweizer.

In the case of China, Hunter and his partners Chris Heinz (John Kerry's stepson) and Heinz's longtime associate Devon Archer began making multi-billion dollar deals "through a series of overlapping entities" after creating several LLCs. In one instance, Schweizer discovered that in 2013, then-Vice President Biden and his son Hunter flew together to China on Air Force Two - and two weeks later, Hunter's firm inked a private equity deal for $1 billion with a subsidiary of the Chinese government's Bank of China, which expanded to $1.5 billion, according to an article by Schweizer's in the New York Post.

Schweizer noted last week in a New York Post Op-Ed that "Hunter Biden at the time had no background in China and had little background in private equity."

"If it sounds shocking that a vice president would shape US-China policy as his son — who has scant experience in private equity — clinched a coveted billion-dollar deal with an arm of the Chinese government, that’s because it is" -Peter Schweizer

Schweizer also referenced a report by The Hill's John Solomon, who reported in early May that in March of 2016, Joe Biden pressured Ukraine's President, Petro Poroshenko, to fire its head prosecutor - who was leading a wide-ranging corruption investigation into the natural gas firm that Hunter sat on, Burisma Holdings.

"I said, ‘You’re not getting the billion.’ I’m going to be leaving here in, I think it was about six hours. I looked at them and said: ‘I’m leaving in six hours. If the prosecutor is not fired, you’re not getting the money,’" bragged Biden, recalling the conversation with Poroshenko.

"Well, son of a bitch, he got fired. And they put in place someone who was solid at the time," Biden said at the Council on Foreign Relations event - while insisting that former president Obama was complicit in the threat.

The former vice president told The New York Times in a recent statement that his son's business dealings was not a consideration in pressuring Ukraine to fire its prosecutor general, noting the decision was made “without any regard for how it would or would not impact any business interests of his son, a private citizen.” Hunter Biden also issued a statement declaring that "at no time have I discussed with my father the company’s business, or my board service, including my initial decision to join the board" of the Ukrainian energy company. -The Hill

Solomon reviewed the general prosecutor's file for the Burisma probe - which he reports shows Hunter Biden, his business partner Devon Archer and their firm, Rosemont Seneca, as potential recipients of money.

And before he was fired, Shokin says he had made "specific plans" for the investigation - including "interrogations and other crime-investigation procedures into all members of the executive board, including Hunter Biden.”