China says it's been open and transparent over origin of Covid-19

China on Tuesday pushed back at renewed suggestions that the COVID-19 pandemic could have been the result of a lab leak, saying it has been open and transparent in the search for the virus' origins.

Recently, the US Department of Energy 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.

The report hasn't been made public and officials in Washington stressed that US agencies are not in agreement on the origin.

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 on Tuesday at a daily briefing.

US officials and members of Congress have accused China of not been entirely cooperative with inquiries into the origin.

A World Health Organisation expert group said last year that key pieces of data to explain how the pandemic began were still missing. The scientists cited avenues of research that were needed, including studies evaluating the role of wild animals and environmental studies in places where the virus might have first spread.

The Associated Press has previously reported that the Chinese government was strictly controlling research into the pandemic's origins, clamping down on some work and promoting fringe theories that it could have come from outside the country.

Politicising the issue of virus tracing will not smear China but will only damage the US's own credibility, Mao said.

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

The US Department of Energy 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. John Kirby, the spokesman for the National Security Council, said on Monday that there is just not an intelligence community consensus on the origin.

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.

Some scientists are open to the lab-leak theory, but many scientists believe the virus came from animals, mutated, and jumped into people as has happened in the past with viruses. Experts say the true origin of the pandemic may not be known for many years if ever.