A preponderance of evidence proves the virus that caused the Covid-19 pandemic leaked from a Chinese research facility, said a report by US Republicans released on Monday, a conclusion that US intelligence agencies have not reached.

The report also cited "ample evidence" that Wuhan Institute of Virology (WIV) scientists - aided by US experts and Chinese and US government funds - were working to modify coronaviruses to infect humans and such manipulation could be hidden.

Representative Mike McCaul, the...