Joe Biden, whose term as vice president had just ended, was to lead the center and was also named a professor at the university.

The National Legal and Policy Center (NLPC), a Virginia-based watchdog, is calling on the U.S. attorney conducting the Hunter Biden investigation in Delaware to look into the situation at UPenn.

In a statement, the university said it had never solicited donations for the Biden Center

The flurry of donations may be related to Hunter Biden's business interests in China, the NLPC alleged in complaints sent to the Departments of Education and Justice.

In total, the Ivy League college took in $54.6 million in donations from China, including $23.1 million in anonymous gifts starting in 2016, most of which came after the establishment of the Biden Center, according to public records.

The Biden Center, which is located in D.C., opened its doors in February 2018. UPenn received $15.8 million in anonymous Chinese gifts that year, including one eye-popping $14.5 million donation in May 2018, records show.

Antony Blinken, whom Biden named as secretary of state, briefly served as the center's managing director.

Last week, the NLPC asked U.S. Attorney David Weiss to step in and investigate the massive Chinese donations to the school as part of his federal tax probe of Hunter Biden.

"We've asked … Weiss to pursue the larger network of individuals and institutions who benefited from millions doled out by foreign interests connected to Hunter Biden's work in China and Ukraine," said Tom Anderson, director of the NLPC's Government Integrity Project.

The NLPC cited a 2017 text found on Hunter Biden's laptop showing that CEFC China Energy Co, one of the firms that Hunter Biden had a financial stake in, wanted to lobby politicians in the U.S. but did not want to register under the Foreign Agent Registration Act, as required for all foreign lobbyists.