The US health secretary has urged the World Health Organization to ensure the next phase of investigation into origins of COVID-19 is transparent.
Speaking to a ministerial-level WHO meeting, Xavier Becerra said international experts should be allowed to evaluate the source of coronavirus.
US media reports suggest growing evidence the virus could have emerged from a laboratory in China.
COVID-19 was first detected in 2019 in Wuhan, in central Hubei province of China.
Since then, more than 167 million cases and 3.4 million deaths have been reported worldwide.
In March this year, the WHO issued a report written jointly with Chinese scientists on the origins of COVID-19, and said the chances of it having started in a lab were extremely unlikely.
Reports attributed to US intelligence sources say three members of the Wuhan Institute of Virology were admitted to hospital in November 2019, several weeks before China acknowledged the first case of the new disease in the community.
Beijing has angrily rejected the reports, repeatedly suggesting the virus may have come from a US laboratory instead.