(CNN) Former Vice President Joe Biden 's son Hunter Biden announced that he will resign at the end of the month from his board role in the management company of a private equity fund backed by Chinese state-owned entities, according to a statement released Sunday by his attorney.

The announcement comes as President Donald Trump continues to lash out at the Bidens amid a House impeachment inquiry into his attempts to pressure Ukrainian President Volodymyr Zelensky to investigate the former vice president during a July 25 phone call. That call is the focus of a whistleblower complaint at the center of Democrats' probe.

Trump has pushed an unproven accusation that Joe Biden was improperly trying to help Hunter, who served on the board of a Ukrainian natural gas company, when the then-vice president pressured the Ukrainian government to fire the country's prosecutor general. The Obama administration, American allies, the International Monetary Fund and Ukrainian anti-corruption activists, among others, had all made clear that they were displeased with the performance of Viktor Shokin, who became prosecutor general in 2015.

There is no evidence of wrongdoing by either Joe or Hunter Biden.

Hunter Biden also pledged to not work for any foreign-owned companies or serve on their boards should his father be elected President, according to the statement provided by attorney George Mesires. Bloomberg first reported Biden's pledge and decision to step down.

"Hunter always understood that his father would be guided, entirely and unequivocally, by established U.S. policy, regardless of its effects on Hunter's professional interests," the statement said. "He never anticipated the barrage of false charges against both him and his father by the President of the United States."

A Biden campaign adviser said they were alerted yesterday the announcement was coming, but didn't know prior to that. The adviser also didn't know why it had taken weeks for this to happen, referring questions on that to Hunter Biden's lawyer. The person noted that Joe Biden has a far stricter standard now than Trump does for his children.

A Biden spokesman told CNN the campaign has no additional comment on the statement from Hunter Biden's lawyer.

But Biden addressed the impeachment inquiry into Trump later Sunday while speaking with reporters in Altoona, Iowa, at the United Food and Commercial Workers forum.

When asked why voters should care about impeachment, he acknowledged that he was a target of Trump's rhetoric but suggested that the inquiry was inevitable.

"I may be the last guy to publicly call for impeachment, but I'm the reason there is impeachment going on," he said, later adding: "I think there's no choice at this point, none whatsoever. Not just because I'm the target, he's not hurting me."