State Department leaders were warned not to pursue an investigation into the origins of COVID-19, former department officials confirmed to Fox News on Thursday, amid fears that it would bring attention to U.S. funding of research at the Wuhan Institute where the virus may have escaped.

Vanity Fair reported that officials calling for transparency from the Chinese government were told not to explore the Wuhan Institute of Virology’s "gain of function" research, because it would bring what the outlet described as "unwelcome" attention of U.S. government funding into that research.

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The outlet reported that Thomas DiNanno, a former acting assistant secretary of the State Department’s Bureau of Arms Control, Verification, and Compliance, wrote in a January memo that staff from two bureaus "warned" leaders within his office not to probe the origins of the virus because it risked opening "a can of worms."

Multiple former State Department officials told Fox News that the reported memo accurately describes what was happening at State at the time and that there was an effort among some officials at the department to oppose an extensive investigation into a possible lab leak.

However, a State Department spokesperson told Fox News on Thursday that "no-one prevented the disclosure of accurate, properly contextualized information" and that "no effort was made at any time to suppress or withhold information from senior policymakers or the public." 

The claims come amid fresh scrutiny over the theory that the COVID-19 pandemic could have escaped from the Wuhan lab, where viruses were being experimented on and where officials have said military research was being conducted alongside civilian research.

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The theory was promulgated by a number of Trump officials -- including President Trump himself -- but was dismissed by many in the media and scientific community, where it was often declared to be debunked or a conspiracy theory.

But with Chinese stonewalling of a World Health Organization investigation into the origins of the virus, and reporting that multiple employees of the lab became sick in November 2019 that required hospitalization, the theory has reemerged. 

The lengthy Vanity Fair piece delves into the back-and-forth at the State Department over how intensely to investigate the Chinese origins of the virus. The outlet reports that Chris Ford, then the acting undersecretary for Arms Control and International Security, was disinterested and even hostile to an investigation.

In a memo in January 2021, Ford pushed back against a panel of experts’ initial investigation, which he believed contained weak evidence, and warned "against suggesting that there is anything inherently suspicious—and suggestive of biological warfare activity—about People’s Liberation Army (PLA) involvement at WIV on classified projects. 

"It would be difficult to say that military involvement in classified virus research is intrinsically problematic, since the U.S. Army has been deeply involved in virus research in the United States for many years," he said, according to Vanity Fair.

It was with that that DiNanno pushed back with a memo of his own, reportedly accusing Ford of misrepresenting the panel’s finding -- while objecting to "apprehension and contempt" from staff as well as warnings not to investigate the origins out of fear of opening a "can of worms."

The State Department spokesperson told Fox News that "internal disagreements were about the quality of analysis and the importance of not overstating, or bending, evidence to fit preconceived narratives."

The spokesperson stressed that getting to the bottom of the pandemic is not about assigning blame but about understanding how to prepare for future pandemics, and that the government investigation has so far coalesced around two likely scenarios but has not yet come to a definitive conclusion. The spokesperson noted a request to the intelligence community by Biden to intensify its probe into the origins of the virus, which may ultimately require questions for China. 

"Importantly, we will continue pushing for a stronger, multilateral evaluation of the origins of the virus in China. We need the PRC to participate in a full, transparent, evidence-based international study with the needed access to get to the bottom of a virus that's taken more than 3 million lives across the globe — and, critically, to share information and lessons that will help us all prevent future catastrophic biological threats," the spokesperson said.

Ford told Fox News on Thursday that he was "not aware of any effort to quash inquiry into possible laboratory origin, and certainly would have opposed it if I encountered one." 

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"I always supported looking at this possibility.  But it was also my position from the outset that until we had actually vetted AVC’s [Bureau of Arms Control, Verification and Compliance’s] particular scientific allegations of WIV origin with real scientists, we shouldn't voice them in public, do demarches, or find China in violation of the Biological Weapons Convention over SARS-CoV-2.  It was irresponsible of AVC to try to run with this before ascertaining whether its scientific claims could survive scrutiny," he said in a statement. "That's why I insisted upon vetting."

"When AVC's own hand-picked panel of experts identified flaws in the 'statistical' argument that AVC had been making since early December, I conveyed this to my colleagues -- accurately and in detail on January 8 -- and I don't regret doing so," he said. 

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Contractor David Asher, who ran the investigation into the origins of the virus, told Fox News last month that some State Department colleagues "were deliberately playing down possible links to China’s biological weapons program."

"At the State Department in the last months of the last administration we didn’t draw or assert any conclusions, but we worked successfully to reveal certain facts and raise significant questions about the clear plausibility of a lab leak origin," Asher said. "This was a global public service, and it is good that experts and journalists are increasingly turning their own attention to the issue, albeit belatedly." 

Fox News' Brooke Singman and Jennifer Griffin contributed to this report.