Acting White House chief of staff Mick Mulvaney on Thursday walked back comments he made earlier in the day suggesting that President Donald Trump held up military aid to Ukraine until it moved to investigate a conspiracy involving the 2016 U.S. election.

"There was absolutely no quid pro quo between Ukrainian military aid and any investigation into the 2016 election," he said in a statement, contradicting remarks he made during an earlier press briefing.

"The president never told me to withhold any money until the Ukrainians did anything related to the server. The only reasons we were holding the money was because of concern about lack of support from other nations and concerns over corruption," he added.

Speaking with reporters at the White House earlier Thursday, Mulvaney said part of the reason the aid to Ukraine was held up was because the president had concerns about corruption in Ukraine related to the 2016 election. Mulvaney said the president also has a strong distaste for foreign aid and doesn't like "spending money overseas."

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"So the demand for an investigation into the Democrats was part of the reason he ordered to withhold funding to Ukraine?," ABC's Jonathan Karl asked.

"The look back to what happened in 2016 certainly was part of the thing he was worried about in corruption with that nation, and that is absolutely appropriate," Mulvaney said.

Karl pressed Mulvaney, saying, "To be clear: what you just described is a quid pro quo. It is 'funding will not flow unless the investigation into the Democratic server happened, as well.'"

"We do that all the time with foreign policy," Mulvaney responded, adding that the administration had also held up money to three Central American countries so that they would change their immigration policies.

"Get over it," he said. "There’s going to be political influence in foreign policy."

Mulvaney's admission angered and confused allies of Trump inside and outside the administration, according to two people familiar with the matter. One of them called Mulvaney’s comments in the White House briefing room "an unmitigated disaster."

Trump and his allies have for the past month insisted no quid pro quo took place regarding Ukraine. House Democrats opened an impeachment inquiry into the president after a whistleblower filed a complaint over Trump's July 25 phone conversation with Ukrainian President Volodymyr Zelenskiy and the administration's subsequent response.

In a White House summary of the call, Trump asked Zelenskiy for a "favor" shortly after the latter discussed U.S. military aid. That favor included asking Zelesnkiy to probe a baseless conspiracy theory about a Democratic National Committee email server being in Ukraine, as well as former Vice President Joe Biden and his son Hunter.

House Intelligence Committee Chairman Rep. Adam Schiff, D-Calif., who is spearheading the impeachment inquiry, reacted to Mulvaney's Thursday comments by saying that the situation has "gone from very, very bad to much, much worse."

Mulvaney on Thursday insisted that the holdup had "absolutely nothing to do with Biden."

"I was involved with the process by which the money was held up temporarily, OK?" Mulvaney said. "Three issues for that. The corruption in the country, whether or not other countries were participating in the support of the Ukraine, and whether or not they were cooperating in an ongoing investigation with our Department of Justice. That's completely legitimate."

A senior Justice Department official said in response: "If the White House was withholding aid from Ukraine with regard to any investigation by the Justice Department, that’s news to us."

Asked about Mulvaney's remarks Thursday, Sen. Lisa Murkowski, R-Alaska, said: "You don’t hold up foreign aid that we had previously appropriated for a political initiative. Period."

On whether the admission amounted to evidence of impeachable conduct, Murkowski said she would "need to look exactly to what" Mulvaney said.

Democrats were swift to respond to Mulvaney's remarks. Rep. Eric Swalwell, D-Calif., tweeted that Mulvaney "co-signed" Trump's "confession to the crime." Rep. David Cicilline, D-R.I., asked, "Since Mulvaney just admitted there was a quid pro quo, what are all the Republicans who have been pretending there wasn’t one going to do?"

"So let’s follow up with those Republican members who went on the tv and said there was no quid pro quo now that Mulvaney has enthusiastically admitted to it," Sen. Brian Schatz, D-Hawaii, tweeted. "What’s the new talking point? My guess is 'Caravan! Emails! Jibber jabber! Cheeseburgers!'"

The debunked DNC server conspiracy — known as "CrowdStrike" — seeks to distance Russia from culpability in the hacking of Democratic National Committee emails. CrowdStrike is a cybersecurity firm that investigated the hacking, and the conspiracy theory paints its findings about Russia's hacking efforts as suspect and politically motivated.

Last month, Trump's former homeland security adviser, Tom Bossert, told ABC's "This Week" that the theory is "not only a conspiracy, it is completely debunked," adding that "it has no validity."

"United States government reached its conclusion on attributing to Russia the DNC hack in 2016 before it even communicated it to the FBI, long before the FBI ever knocked on the door at the DNC, he continued. "So a server inside the DNC was not relevant to our determination to the attribution. It was made upfront and beforehand."

"The DNC server and that conspiracy theory has got to go, they have to stop with that, it cannot continue to be repeated in our — in our discourse," Bossert added, saying that if Trump continues to focus on 2016, "it's going to bring him down."