China said it has been “open and transparent” in the search for the origins of the Covid-19 pandemic and dismissed US criticism as politicising the issue.

China has “shared the most data and research results on virus tracing and made important contributions to global virus tracing research”, Foreign Ministry spokesperson Mao Ning Mao told reporters at a daily briefing.

“Politicising the issue of virus tracing will not smear China but will only damage the US’s own credibility,” Ms Mao said, in response to complaints from US officials and members of Congress that China has not been entirely cooperative.

Virus Outbreak China Daily Life
Commuters wearing face masks stand in line for buses during the evening rush hour in the central business district in Beijing (Mark Schiefelbein/AP)

Her comments came amid continuing questions about how the virus that has killed more than 6.8 million people worldwide first emerged.

Most recently, the US Department of Energy (DoE) assessed with “low confidence” that the pandemic that was first detected in the central Chinese city of Wuhan in late 2019 began with the leak of a virus from a lab.

Others in the US intelligence community disagree, citing differing opinions within the government. “There is just not an intelligence community consensus,” John Kirby, the spokesman for the National Security Council, said on Monday.

The US Energy Department’s conclusion was first reported over the weekend in the Wall Street Journal, which said the classified report was based on new intelligence and noted in an update to a 2021 document. The DoE oversees a national network of labs in the US.

White House officials on Monday declined to confirm press reports about the assessment.

In 2021, officials released an intelligence report summary that said four members of the US intelligence community believed with low confidence that the virus was first transmitted from an animal to a human, and a fifth believed with moderate confidence that the first human infection was linked to a lab.