The director of the National Institutes of Health (NIH) said he believes COVID-19 originated in animals, but did not rule out the theory that the virus was created in a lab.
In an appearance on CNBC's Squawk Box on Monday, Dr Francis Collins said the coronavirus does not have 'earmarks' indicating human creation.
However, he said he cannot yet dismiss a scenario in which scientists were studying the pathogen at the Wuhan Institute of Virology and it accidentally escaped.
Collins' statement comes on the deadline set by President Joe Biden for the intelligence community to investigate the origins of the virus.
Findings by officials will largely be private, though some results will be made public.
Dr Francis Collins, director of the NIH, told CNBC on Monday (pictured) that he believes COVID-19 originated in animals, but did not dismiss the lab leak theory
Allegations that COVID-19 leaked from the Wuhan Institute of Virology began in May, when it was reported that employees at the lab contracted the virus before Chinese officials reported the earliest cases. Pictured: A French doctor assists a patient in a COVID-19 ward in Paris.
'The vast evidence from other perspectives says no, this was a naturally occurring virus,' Collins said.
'Not to say that it could not have been under study secretly at the Wuhan Institute of Virology and got out of there, we don't know about that.
'But the virus itself does not have the earmarks of having been created intentionally by human work.'
Collins did criticize Chinese officials for not assisting World Health Organization (WHO) officials in a separate investigation.
'I think China basically refused to consider another WHO investigation and just said 'nope not interested',' Collins said.
'Wouldn't it be good if they'd actually open up their lab books and let us know what they were actually doing there and find out more about those cases of people who got sick in November of 2019 about which we really don't know enough.'
For the past several months, there has been back-and-forth speculation about the origins of COVID-19 and whether it came from wild animals or was manufactured in and accidentally escaped from a laboratory.
In May, a report from The Wall Street Journal, citing a previously undisclosed U.S. intelligence report, detailed how three researchers from China's Wuhan Institute of Virology (WIV) sought hospital care in November 2019, months before China disclosed the COVID-19
