China has responded furiously to US claims there is new evidence Covid-19 was leaked from a laboratory, however Washington is standing firm and demanding Beijing be "more honest".
On Sunday (local time), the US revisited claims the virus spread from the Wuhan Institute of Virology when it was revealed the US Energy Department had upgraded its stance on the theory to "low confidence" following the emergence of "new intelligence".
Claims of possessing evidence stems back to when Donald Trump was president, with former secretary of state Mike Pompeo stressing Washington has significant evidence of a leak.
On Monday, China's foreign ministry scolded the US for revisiting the theory they say has been put to bed.
"The origins-tracing of SARS-CoV-2 is about science and should not be politicised," spokesperson Mao Ning told reporters.
"'A laboratory origin of the pandemic was considered to be extremely unlikely' is a science-based, authoritative conclusion reached by the experts of the WHO-China joint mission after field trips to the lab in Wuhan."
She warned the US to "stop rehashing the 'lab leak' narrative, stop smearing China and stop politicising origins-tracing".
While the 2021 mission did in some way quash the theory, WHO chief Tedros Adhanom Ghebreyesus later admitted such a conclusion was rushed and further investigation was needed. Sections of the external investigating party also raised doubts over how much data was being made available to them.
Many scientists still however back the theory the virus transmitted naturally via the Wuhan Seafood market, with research shared in 2022 suggesting data "overwhelmingly shows" the pandemic began through zoonosis.
The US ambassador to China has since urged Beijing for more transparency on when the virus first emerged in Wuhan in late 2019.
"[China needs to] be more honest about what happened three years ago in Wuhan with the origin of the COVID-19 crisis," Nicholas Burns said via video link to a US Chamber of Commerce event.
US accuses China of blame game
Burns told the Chamber event that it was a difficult moment for US-China relations, with Beijing seeking to deflect blame after the US military this month downed an alleged Chinese spy balloon that drifted across the continental United States.
"We're now in this surreal moment where the Chinese, who I think lost the debate over the balloon globally, lost influence and credibility around the world because of what they've done — they're now blaming this on us," Burns said.
"It's a little bit Orwellian. And it's a little bit frustrating, because I think everybody knows the truth here."
China reacted angrily when the US military downed the balloon on February 4, saying it was for monitoring weather conditions and had blown off course.
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