Wuhan

But US agencies say the virus, first identified in China, was not developed as a biological weapon.

The office that oversees US spy agencies could not establish how the coronavirus pandemic began.

US intelligence was tasked with looking into animal-to-human transfer or a possible lab leak.

The city of 11 million people is known to be the site where the coronavirus first emerged in 2019.

China says a proposal to audit labs shows "disrespect to common sense and arrogance towards science".

Researchers aim to "set the record straight" on how the virus transferred from bats into humans.

Supporters say the former president was "dead on", as the theory about the origins of Covid gains respectability.

China accuses the US of "political manipulation" over investigations into the origins of the pandemic.

The claim Covid-19 may have leaked from a Chinese laboratory is gaining traction. Here's what we know.

US intelligence is divided on whether the virus came from a Chinese lab or animal-to-human contact.

Without mentioning China, the US health secretary says experts must be allowed to evaluate the virus source.

Team investigating the outbreak in Wuhan was unable to get a clear picture of the crucial early weeks.

All possible causes of the pandemic remain on the table, says the WHO, though lab leak least likely.

There has been criticism over the level of access to key data the team was given by the Chinese.