The Chinese virology institute at the centre of the United States allegations that it may have been the source of the Covid-19 pandemic has three live strains of bat coronavirus on-site, but none match the new global contagion, its director has said.

Scientists think Covid-19 originated in bats and could have been transmitted to people via another mammal.

But the director of the Wuhan Institute of Virology told state broadcaster CGTN that claims made by US President Donald Trump and others the virus could have leaked from the facility were “pure fabrication”.