China has angrily rejected White House calls for an investigation into the possibility that Covid-19 escaped from a Wuhan laboratory, a theory that state media described as “a conspiracy created by US intelligence agencies”.

The Biden administration has in recent days begun to push for a fuller investigation into the origins of the pandemic, following a report from the Wall Street Journal. The article said that three employees of the Wuhan Institute of Virology had fallen sick with Covid-19-like symptoms in November 2019, citing an undisclosed US intelligence report.

The Wuhan institute, China’s highest-level biosafety lab, has been at the centre of theories arguing that Sars-Cov-2 may have accidentally infected humans during experiments on bat coronaviruses conducted there.