Yuan said "malicious" claims about the lab had been "pulled out of thin air" and contradicted all available evidence. "The WIV does not have the intention and the ability to design and construct a new coronavirus," and "there is no information within the SARS-CoV-2 genome indicating it was man-made," he told Reuters.

Some conspiracy theories were fuelled by a widely read scientific paper from the Indian Institute of Technology, since withdrawn, claiming that proteins in the coronavirus shared an "uncanny similarity" with those of HIV, the story said.

Most scientists now say SARS-CoV-2 originated in wildlife, with bats and pangolins identified as possible host species. The scientific consensus is that the coronavirus evloved naturally, according to Reuters.

"More than 70 percent of emerging infectious diseases originated from animals, especially wild animals," Yuan told Reuters.

Scientists say that all seven known human coronaviruses have origins in bats, mice or domestic animals.

The lab director also rejected theories that the lab had accidentally released a coronavirus it had harvested from bats for research purposes, saying the lab's biosecurity procedures were strictly enforced, Reuters said.

"High-level biosafety labs have sophisticated protective facilities and strict measures to ensure the safety of laboratory staff and protect the environment from contamination," he said.

He said that his institute was committed to transparency and would share all available data about the coronavirus in a timely fashion.

As for the origin of the virus, Yuan told Reuters that there were "still no answers" about it.

He cited a paper by British and German scientists published this month suggesting that the SARS-CoV-2 variant circulating in the United States was a more "primitive" version of the one in China, and might have appeared there first.