The World Health Organization (WHO) has said that all available evidence suggests coronavirus originated inside bats in China.
In a statement in Geneva on Tuesday, the health body also refuted claims the disease may have been manipulated or constructed in a laboratory.
WHO spokeswoman Fadela Chaib said it was not clear how the virus had jumped the species barrier to humans but there had "certainly" been an intermediate animal host.
"All available evidence suggests the virus has an animal origin and is not manipulated or constructed virus in a lab or somewhere else," she said.
"It is probable, likely that the virus is of animal origin."
It comes as US president Donald Trump launched an investigation into allegations the virus spread from a lab in Wuhan and demanded that China "come clean" about the origins of COVID-19.
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“Let’s see what happens with their investigation. But we’re doing investigations also,” Trump said at a White House news conference on Saturday.
“If it was a mistake, a mistake is a mistake. But if they were knowingly responsible, yeah, then there should be consequences.”
The investigation was announced after Fox News reported that unnamed sources believe the virus was initially transmitted from a bat to a human in a virology lab in Wuhan.
"What we do know is we know that this virus originated in Wuhan, China," US secretary of state Mike Pompeo told Fox in response to the report. "We know there is the Wuhan Institute of Virology just a handful of miles away from where the wet market was.
“There is still lots to learn,” he added, “The United States government is working diligently to figure it out."
According to a recent study carried out by polling agency YouGov, 70% of the British public think it is “probably true” that the source of COVID-19 pandemic was a live animal market in China.
Of the 1,600 people surveyed, 17% believed it was “definitely true”.
Just over half of Britons, 53%, think it is either definitely true or probably true that the virus was transmitted to humans via wild animals such as bats, pangolins and snakes.