Hunter Biden and associates started working with CEFC, a Chinese firm linked to the ruling communist party, in 2015.

But payments for the work did not start flowing until after President Biden in January 2017 departed as vice president, Rob Walker, the former partner of Hunter Biden, was said to have told members.

"Today's interview confirmed Hunter Biden and his associates' work with the Chinese government-linked energy company began over a year before Joe Biden left the vice presidency, but the Bidens and their associates held off being paid by the Chinese while Joe Biden was in office," Rep. James Comer (R-Ky.), chairman of the U.S. House of Representatives Oversight Committee, said in a Jan. 26 statement.

President Biden was vice president from 2009 to 2017.

Mr. Walker, who testified behind closed doors, could not be reached.

In a prepared opening statement, Mr. Walker said that he spent years pursuing "legitimate business" with Mr. Biden and that President Biden "was never involved in any of the business activities we pursued."

"Hunter made sure there was always a clear boundary between any business and his father," Mr. Walker said.

The White House said that Mr. Walker's testimony had refuted Republican claims about President Biden.

Rep. Jamie Raskin (D-Md.), ranking member of the House Oversight Committee, said that "Mr. Walker reaffirmed today what we already know by now: Joe Biden was not involved in, did not profit from, and took no official actions in relation to his family's business dealings."