The admission provides a new dimension to the ongoing impeachment inquiry into Trump, which centers on Democrats’ allegations that he withheld U.S. military aid for Ukraine as he pressured Zelensky for an investigation into former Vice President Joe Biden and his son Hunter. Trump's comments about a potential China probe came shortly after he discussed how the two superpowers are locked in intense trade negotiations.

Trump noted — also unprompted — that Chinese negotiators would be in town next week as the high-stakes trade talks resume, with potentially billions of dollars in tariffs on the line.

“I have a lot of options on China,” he said of the trade talks, “but if they don't do what we want, we have tremendous power.”

Trump has repeatedly hammered Hunter Biden's foreign business dealings over the last few weeks as he's defended urging the Ukrainian president to open an investigation during a July phone call. That call, and a whistleblower complaint raising alarms about his request, have landed the president in the middle of an impeachment inquiry in Congress.

Thursday’s comments by the president came as House lawmakers grilled behind closed doors the first witness for their impeachment investigation, Trump’s former Ukraine envoy Kurt Volker.

Trump’s public appeals for foreign governments to probe a potential political opponent — Biden is one of the top contenders to take on Trump in next year's election — was reminiscent of the Russia probe that engulfed the first half of Trump’s first term, which examined, in part, his 2016 invitation for Russia to hack Hillary Clinton’s emails.

House Intelligence Chairman Adam Schiff, a leader of the House's impeachment inquiry and one of Trump's chief congressional foes, reiterated in a tweet that "the President cannot use the power of his office to pressure foreign leaders to investigate his political opponents."

Trump's "rant this morning reinforces the urgency of our work," he added.

Speaking to reporters at the Capitol after reemerging from Volker's testimony, Schiff went even further, calling Trump's overtures "repugnant" and "a fundamental breach of the president's oath of office."

He cast the developments as a direct result of a lack of accountability, contending that the president's behavior "is an illustration that this president, if he's learned anything from the two years of the Mueller investigation, it's that he feels he can do anything with impunity."

Speaker Nancy Pelosi was just as blunt, writing in a tweet that his remarks Thursday are "just the latest example of him putting his personal political gain ahead of defending the integrity of our elections."

“The president has confessed to a violation of his oath of office” she later told reporters in Weston, Fla. “Our founding fathers were very suspicious of foreign interference in our government.”

Trump and his allies have claimed that Hunter Biden convinced China to put $1.5 billion in a fund for an investment firm he had a stake in, assertions lawyers for the former vice president's son have denied. George Mesires, Hunter Biden’s lawyer, has told multiple media outlets that he did not have a financial stake in the firm until after his father left public office.

Biden critics have pointed to a trip to China in 2013 that Joe Biden took while vice president. Hunter and his daughter accompanied his father on the trip, where he arranged a meeting between the vice president and a Chinese banker involved with the firm, though Hunter Biden's lawyer denied any business was conducted on the trip.

The president and his allies have also suggested that Biden used his father's influence to get ahead in business — Trump accused Biden on Thursday of giving China a “sweetheart deal” due to his son’s business interests there. He also accused Hunter Biden, without evidence, of receiving a “payoff” from the Chinese.

Mesires told The Washington Post last week that Hunter had not received “any return or compensation” from his investment or role with the firm, and that Trump and his defenders had engaged in a “gross misrepresentation” of Hunter’s role there.

The former vice president has also forcefully denied any wrongdoing by himself or his son and has repeatedly insisted he and Hunter did not discuss his business interests.

At the White House on Thursday, Trump predicted that the Bidens' business dealings would weigh heavily on the former vice president's campaign.

“Well, I think Biden is going down, and I think his whole situation, because now you may very well find that there are many other countries that they scam just like they scam China and Ukraine," Trump said.

Vice President Mike Pence continued to defend Trump on Thursday, but did not directly address a question from reporters about the president's latest entreaty to Beijing and instead defended Trump's request of Zelenksy.

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"I think the American people have a right to know if the vice president of the United States or his family profited from his position as vice president during the last administration. That is about looking backwards and understanding what really happened," he told reporters during a trip to Arizona, asserting that Trump's push falls under his campaign promise to "drain the swamp."

"I mean, the fact that my predecessor had a son who was paid $50,000 a month to be on a Ukrainian board, at the time that Vice President Biden was leading the Obama administration's efforts in Ukraine, I think it's worth looking into," Pence continued. "And the president made it very clear that he believes other nations around the world should look into it, as well."

Pence also argued that the business dealings of the Biden family were fair game because of the "unique responsibilities" that came with his position of power. Biden, he said, should have worked as vice president to avoid not just impropriety, but even the "appearance of impropriety," an accusation that mirrored claims often leveled against Trump and his adult children by Democrats.

Democrats, meanwhile, reacted with indignation to the president’s latest pronouncements.

Biden’s campaign shredded the president in a statement put out shortly after Trump lifted off from the White House lawn, claiming that the “defining characteristic of Donald Trump's presidency is the ongoing abuse of power.”

“What Donald Trump just said on the South Lawn of the White House was this election's equivalent of his infamous 'Russia, if you're listening' moment from 2016 — a grotesque choice of lies over truth and self over the country,” deputy campaign manager Kate Bedingfield said. “The White House itself has admitted that Donald Trump tried to bully a foreign country into lying about the domestic opponent he's afraid to look in the eye next November.”

Bedingfield accused the president of “desperately clutching for conspiracy theories that have been debunked and dismissed by independent, credible news organizations,” and called his foreign overtures proof that the president is threatened by Biden’s candidacy.

At least one of Biden’s rivals for the Democratic nomination, Sen. Kamala Harris, also came to his defense, warning in a tweet directed at Trump that “telling lies about Joe Biden won't protect you from the truth.” Others reiterated their calls for Trump’s impeachment.

Schiff issued a challenge to his Republican colleagues in Congress, declaring that Trump's outreach "endangers our elections, it endangers our national security. It ought to be condemned by every member of this body, Democrats and or Republicans alike."

Clinton, Trump’s 2016 opponent who only recently leaned in fully to calling for impeachment, wrote on Twitter that “Someone should inform the president that impeachable offenses committed on national television still count.”

Ellen Weintraub, the Democratic head of the Federal Election Commission also weighed in, re-upping a June statement clarifying the commission’s guidelines about foreign interference in American elections. “Is this thing on?” she wrote, adding a microphone emoji.

Andrew Desiderio and Marc Caputo contributed to this report.