The head of the World Health Organization told the Financial Times he was ready to send a new mission of experts to China to investigate the origins of Covid-19.
"We're pressing China to give full access, and we are asking countries to raise it during their bilateral meetings -- (to urge Beijing) to co-operate," Tedros Adhanom Ghebreyesus told the FT.
He said the WHO had already written to China asking "to give us information " and for the organisation to send a team "if they allow us to do so".
The international community has been unable to determine with certainty the origins of the Covid pandemic.
The first cases were detected at the end of 2019 in Wuhan, China, suggesting two opposing theories: an escape from a laboratory in the city where such viruses were being studied or an intermediate animal that infected people at a local market.
A team of specialists led by the WHO and accompanied by Chinese colleagues had investigated China in early 2021.
In a joint report, they favoured the hypothesis that the virus had been transmitted by intermediary animal from a bat to a human, possibly at a market.
Tedros said after that all options remained "on the table".
There has not been a team able to return to China and WHO officials have repeatedly asked for additional data.
Tedros has repeatedly said the WHO would not abandon its investigation and has called on Beijing for transparency in sharing data, carrying out investigations and sharing the results.
The WHO lifted the highest alert level that had been in place for the pandemic earlier this year.
Thanks to vaccines, post-infection immunity and better treatment, the virus is now under greater control, although with the arrival of autumn in the Northern Hemisphere, new variants are emerging.
