COVID-19 is likely to have leaked from a Wuhan laboratory.
COVID-19 is likely to have leaked from a Wuhan lab
The US Energy Department has produced a report for politicians, which has been seen by The Wall Street Journal newspaper, that suggested that a lab leak was the most likely reason for the emergence of the virus.
The agency had previously been "undecided" on how the virus appeared and did add that it was not being engineered by China as part of a weapons programme.
The FBI also believes that a lab leak is the most likely source of COVID-19 but four other US agencies say it was probably the result of natural transmission.
White House national security adviser Jake Sullivan explained that there are still a "variety of views" on the subject and that President Joe Biden is determined to explore every possibility.
He said: "President Biden specifically requested that the national labs, which are part of the Energy Department, be brought into this assessment because he wants to put every tool at use to be able to figure out what happened here."