U.S. President Donald Trump has publicly called on China to investigate Democratic presidential hopeful Joe Biden, amid an impeachment inquiry in Congress over his request for Ukraine to investigate Biden and his son, Hunter.

Trump told reporters at the White House on October 3 that he believed both China and Ukraine should look into former Vice President Biden and his businessman son, and described the impeachment probe as 'crap.'

'I would say that [Ukrainian] President [Volodymyr] Zelenskiy, if it were me, I would recommend that they start an investigation into the Bidens,' Trump said.

'Likewise, China should start an investigation into the Bidens, because what happened in China is just about as bad as what happened with Ukraine.'

Asked if he had requested President Xi Jinping do the same, Trump replied, 'I haven't, but it's certainly something we can start thinking about.'

Trump later tweeted that it was his duty to investigate corruption.

'As the President of the United States, I have an absolute right, perhaps even a duty, to investigate, or have investigated, CORRUPTION, and that would include asking, or suggesting, other Countries to help us out!' Trump wrote on Twitter.

The United States and China are embroiled in a bitter trade war that has impacted global economic growth.

CNN reported that during a phone call with Xi on June 18, Trump raised Biden's political prospects. Quoting two unnamed people familiar with the discussion, CNN said that during the call, Trump also told Xi he would remain quiet on Hong Kong protests as trade talks progressed.

The Chinese Embassy in Washington did not immediately respond to a request for comment. A new round of trade negotiations between the world's two largest economies is set for next week.

Biden's son Hunter was on the board of the Ukrainian gas company Burisma at the same time his father was leading the Obama administration's dealings with Kyiv. No evidence has been presented indicating any wrongdoing by Joe or Hunter Biden in the case.

Some Republicans have criticized Biden for taking Hunter on the vice-presidential plane in 2013 to China, where Hunter had business interests.

During a health-care event in Florida, Trump said Democrats had launched the impeachment investigation because they could not defeat him at the ballot box in 2020.

'That's why they do the impeachment crap -- they know they can't win,' Trump said.

With reporting by Reuters, AFP, AP, CNN, and BBC

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