Saying the potential conflicts of interest were reminiscent of the controversial "Uranium One" transaction, Senate Finance Committee Chairman Chuck Grassley announced Thursday he is probing the Obama administration's 2015 decision to approve the sale of a sensitive U.S. technology company to the Chinese government and an investment firm run by the sons of Joe Biden and John Kerry.

Hunter Biden's business dealings in Ukraine have already become a liability for the elder Biden's frontrunning presidential campaign, and the new investigation could lead to further allegations of corruption. Joe Biden has bragged about pressuring Ukraine to fire its top prosecutor in 2016, and critics said the then-vice president wanted to head off the prosecutor's probe into a company that employed Hunter Biden as a board member.

Grassley, writing to Treasury Secretary Steven Mnuchin, noted that Rosemont Seneca Partners, which was established by Kerry stepson Christopher Heinz and Hunter Biden, among others, joined with the government-run Bank of China to create Bohai Harvest RST (BHR) in 2013. The fund openly advertised its “unique Sino-US shareholding structure," as well as its lucrative “global resources and network."

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In 2015, BHR and the state-owned military contractor Aviation Industry Corporation of China (AVIC) jointly purchased Henniges, a U.S.-based automotive company that creates "dual-use" technologies with both military and civilian applications. including anti-vibration technology. AVIC purchased 51 percent of Henniges, while BHR took 49 percent.

Hunter Biden and Joe Biden have faced scrutiny in recent weeks for overseas business dealings -- which could become a liability in 2020. (Photo by Teresa Kroeger/Getty Images for World Food Program USA)

The Obama administration’s Committee on Foreign Investment in the United States (CFIUS), by law, had to approve the sale because of its national security implications. The CFIUS is an interagency body consisting of, among other agencies, the Energy Department, Defense Department, Treasury Department, and State Department -- which John Kerry led from 2013 to 2017.

"CFIUS approved the transaction despite reports that in 2007, years before BHR teamed up with AVIC’s subsidiary, AVIC was reportedly involved in stealing sensitive data regarding the Joint Strike Fighter program. AVIC later reportedly incorporated the stolen data into China’s J-20 and J‑31 aircraft," Grassley wrote to Mnuchin.

Grassley continued: "The direct involvement of Mr. Hunter Biden and Mr. Heinz in the acquisition of Henniges by the Chinese government creates a potential conflict of interest. Both are directly related to high-ranking Obama administration officials. The Department of State, then under Mr. Kerry’s leadership, is also a CFIUS member and played a direct role in the decision to approve the Henniges transaction."

"The appearance of potential conflicts in this case is particularly troubling given Mr. Biden’s and Mr. Heinz’s history of investing in and collaborating with Chinese companies, including at least one posing significant national security concerns," Grassley added. "As with the Uranium One transaction, there is cause for concern that potential conflicts of interest could have influenced CFIUS approval of the Henniges transaction."

Grassley has separately sought documents that allegedly show that federal officials failed to investigate possible criminal activity related to Hillary Clinton, the Clinton Foundation and Rosatom, the Russian nuclear company whose subsidiary purchased the Canadian mining company Uranium One in 2013.

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Grassley specifically demanded, by Aug. 29, a "copy of the National Security Threat Assessment for the Henniges transaction," as well as a detailed explanation of "each stage of the CFIUS review process for the Henniges acquisition."

"Did CFIUS, or any of its members, brief the President and/or White House personnel on the Henniges transaction?" Grassley wrote. "If so, when was the briefing provided, who provided the briefing, and who was briefed? Was the Henniges transaction subject to a national security arrangement? If so, please provide the documentation of the arrangement.  If it was not subject to such an arrangement, why not?"

The probe comes as the 2020 presidential campaign increasingly focuses on international relations and potential corruption. President Trump has openly suggested the Justice Department may probe the Biden business dealings abroad. And amid the escalating trade war with China, Trump has attacked Biden as clueless on the issue.

In May, Joe Biden downplayed again the threat posed by China, saying the Chinese economy or its influence won’t overtake the U.S., reiterating his previous stance that China is not a competitor.

“What are we doing? We're walking around with our heads down, 'Woe is me,'” the leading 2020 Democrat told a crowd of supporters. “No other nation can catch us, including China. I got criticized for saying that. I've spent as much time with [Chinese President] Xi Jinping as any world leader has.”

Separately, Biden said: "China is going to eat our lunch? Come on, man!" Biden exclaimed. "The fact that they have this great division between the China Sea and the mountains in the East -- I mean in the West. They can't figure out how they're going to deal with the corruption that exists within the system. They're not bad folks, folks. But guess what, they're not competition for us."

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Reacting to those remarks, Trump told Fox News in May that Biden was among many politicians "naive" over China.

"For somebody to be so naive, and say China's not a problem -- if Biden actually said that, that's a very dumb statement," Trump said.