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 top Republican on the House Foreign Affairs Committee, released the report by the panel's Republican staff. It urged a bipartisan investigation into the origins of the Covid-19 coronavirus pandemic that has killed 4.4 million people worldwide.
China denies a genetically modified coronavirus leaked from the facility in Wuhan - where the first Covid-19 cases were detected in 2019 - a leading but unproven theory among some experts. Beijing also denies allegations of a cover-up.
Other experts suspect the pandemic was caused by an animal virus likely transmitted to humans at a seafood market near the WIV.