United States President Donald Trump has raised the prospect that China deliberately caused the Covid-19 outbreak, saying there should be consequences if the country is found to be "knowingly responsible".
In his comments at a media briefing last Saturday, the President said the US was conducting its own investigations on how the pandemic started.
Mr Trump has said his government is seeking to determine if the coronavirus came from a high-security laboratory in Wuhan, the epicentre of the outbreak in China, after a Fox News report last week alleged the same, citing unnamed sources.
Professor Yuan Zhiming, director of the laboratory, has rejected the claim, calling it "impossible". None of his staff had been infected, he told state broadcaster CGTN last Saturday.
Chinese scientists have said the virus likely jumped from an animal to humans in a wildlife market.