Dr. Anthony Fauci, the scientific face of America’s pandemic response, dismissed the theory that coronavirus originated in a lab in Wuhan, contradicting the president and his Secretary of State in an escalating confrontation with China.

“The best evidence shows the virus behind the pandemic was not made in a lab in China,” Dr. Anthony Fauci said in an exclusive interview with National Geographic published on Monday. “Everything about the stepwise evolution over time strongly indicates that [this virus] evolved in nature and then jumped species.”

He added that he doesn’t believe the alternate theory that someone discovered coronavirus in the wild, brought it to a lab and then it accidentally unleashed it on the public.

Fauci’s statement contradicts an April 30 comment by President Donald Trump that he had seen convincing evidence that the coronavirus originated from China’s Wuhan Institute of Virology (WIV). On Sunday, U.S. Secretary of State Mike Pompeo said he’d seen “enormous evidence” supporting the theory, but didn’t elaborate.

The New York Times also reported last week the administration is pressuring some within the intelligence community to lend weight to the WIV theory. There is not yet any publicly available evidence supporting the WIV’s involvement in the pandemic.

U.S. intelligence has concluded that the COVID-19 novel coronavirus was neither man-made nor genetically modified, though officials are investigating whether it could have been released from the WIV.

China has roundly rejected any accusation that it mishandled the outbreak or that the WIV was involved in the pandemic. On Monday, The Global Times newspaper—owned by the official publication of the Chinese Communist Party—published an editorial demanding that Pompeo provide any evidence for his claim, suggesting he was “bluffing.”

The Chinese government has often rejected criticisms that it mishandled the epidemic, stating that international critics are merely spreading propaganda to distract from their own countries’ mistakes during the pandemic.

Trump and Pompeo’s claim about the WIV lab has escalated tensions between the U.S. and China. Officials at the U.S. Department of Homeland Security (DHS) have accused China of concealing the severity of the epidemic early on to hoard medical supplies.

The DHS report also claimed that Chinese leaders deliberately didn’t notify the World Health Organization (WHO) of the virus’ contagion status through most of January to downplay its severity.

The Embassy of the People’s Republic of China in the U.S told Newsweek that it considered the report just another “groundless accusation.”

Regardless, a May 1 poll from The Economist and YouGov found that almost twice as many Republicans as Democrats now see China as an “enemy” of the state since the U.S. coronavirus outbreak began. The poll also revealed that ne

arly half of all Americans believe that the virus was “definitely” or “probably” created in a lab. While 29 percent of Democrats believed the statement, more than two-thirds of Republicans did.

The public feud over the lab has coincided with the escalation of military tensions. Last Tuesday, the U.S. Navy sailed a second ship through the South China Seas, challenging China’s claim to the disputed waters. China’s armed forces, the People’s Liberation Army (PLA), said that it had expelled the first U.S. Naval ship, the USS Barry.

The Chinese military’s social media accused the U.S. of violating “international law and China’s sovereignty and security interests” through “provocative acts,” calling the sailing of ships “incompatible with the current joint efforts of the international community to fight against the Covid-19,” according to the South China Morning Post.

“These provocative acts by the U.S. side … seriously violated China’s sovereignty and security interests, deliberately increased regional security risks and could easily trigger an unexpected incident.”

However, a Navy spokesperson denied that the PLA forced the USS Barry out of the disputed waters, telling Newsweek last Wednesday that “all interactions that occurred were in accordance with maritime norms.”

Fauci, the director of the National Institute of Allergy and Infectious Diseases (NIAID) and a prominent member of President Donald Trump’s coronavirus task force, joins task force response coordinator Dr. Deborah Birx in their doubt of Trump and Pompeo’s claim.

In a Sunday appearance on CBS News’ Face the Nation, Dr. Birx said the evidence is lacking to prove that the coronavirus epidemic began from an accident in the Wuhan laboratory.

On April 28, Newsweek reported that NIAID funded scientists at the WIV and other institutions for work on gain-of-function research on bat coronaviruses. The WIV’s work on bat coronaviruses explains the Trump administration’s focus on the lab as a possible culprit for the epidemic.

In 2019, the NIAID provided backing for the National Institutes of Health (NIH) to commit $3.7 million over six years to the WIV for research including some studies into gain-of-function. This money came after another $3.7 million, 5-year project for studying various bat coronaviruses. That project concluded in 2019. The NIH canceled the latest $3.7 million project on Friday, April 24, Politico reported.

Richard Ebright, an infectious disease expert at Rutgers University, noted that the project description would’ve involved enhancing bat coronavirus to infect human cells and lab animals using genetic engineering techniques.

Ebright and other scientists have opposed gain-of-function research because it risks the possibility of accidentally releasing the virus from a lab and creating a pandemic.

“Determining the molecular Achilles’ heel of these viruses can allow scientists to identify novel antiviral drug targets that could be used to prevent infection in those at risk or to better treat those who become infected… [creating] a critical foundation for generating appropriate countermeasures and, ultimately, protecting the public health,” Dr. Fauci and two co-authors wrote in a December 30, 2011 Washington Post article defending their work.

When asked about his slow response to addressing coronavirus, Trump said during a Fox News town hall on Sunday night that Dr. Fauci among others told him they expected the virus wouldn’t be too serious.

“Nancy Pelosi was a month later saying it was going to pass—everybody, even Tony Fauci, was saying it’s going to pass, not going to be a big deal,” Trump said.

However, in a 2017 Georgetown University speech, Fauci said, “There is no question that there will be a challenge to the coming administration in the arena of infectious diseases,” adding, “The thing we’re extraordinarily confident about is that we’re going to see this in the next few years.”

While the White House blocked Dr. Fauci, from testifying before Democrat-led House Appropriations Committee as a witness at a subcommittee hearing on Covid-19 responses, he is set to appear before the Republican-led Senate Committee on Health, Education Labor and Pensions on May 12, according to MSN.com.