Top U.S. infectious disease expert Anthony Fauci said that SARS-CoV-2, the virus that causes COVID-19, could not have been artificially or deliberately manipulated.

Fauci, director of the National Institute of Allergy and Infectious Diseases, made the comments Monday in an interview with National Geographic.

While answering a question regarding evidence that the virus was made in or accidentally released from a lab in China, Fauci said, "If you look at the evolution of the virus in bats, and what's out there now is very, very strongly leaning toward this (virus) could not have been artificially or deliberately manipulated -- the way the mutations have naturally evolved."

"A number of very qualified evolutionary biologists have said that everything about the stepwise evolution over time strongly indicates that it evolved in nature and then jumped species," he said.

Asked about the possibility that the virus was found outside the lab, then brought back and escaped, Fauci said, "That means it (virus) was in the wild to begin with."

"That's why I don't get what they're talking about (and) why I don't spend a lot of time going in on this circular argument," he said.