The director of China’s Wuhan lab has rejected claims that it could be the source of the coronavirus outbreak.
He said it was “impossible” for the lab to have generated the viruss.
Beijing has come under increasing pressure over transparency in its handling of the pandemic.
The U.S. said it has begun a probe on whether the virus actually originated in the lab.
Chinese scientists have said the virus likely jumped from an animal to humans in a market that sold wildlife.
But the existence of the facility and its its P4 laboratory which is equipped to handle dangerous viruses, has fuelled conspiracy theories that the germ spread from the Wuhan Institute of Virology.
In an interview with state media published Saturday Yuan Zhiming, director of the laboratory, said that “there’s no way this virus came from us”.
None of his staff had been infected, he told the English-language state broadcaster CGTN, adding the “whole institute is carrying out research in different areas related to the coronavirus”.
The institute had already dismissed the theory in February, saying it had shared information about the pathogen with the World Health Organisation in early January.
But this week the United States has brought the rumours into the mainstream.
Secretary of State Mike Pompeo said U.S. officials are doing a “full investigation” into how the virus “got out into the world”.
When asked if the research suggested the virus could have come from the institute, Yuan said: “I know it’s impossible.”
“As people who carry out viral studies we clearly know what kind of research is going on at the institute and how the institute manages viruses and samples,” he said.
He said that because the P4 laboratory is in Wuhan “people can’t help but make associations”, but that some media outlets are “deliberately trying to mislead people”.
Reports in the Washington Post and Fox News have both quoted anonymous sources who voiced concern that the virus may have come — accidentally — from the facility.
Yuan said the reports were “entirely based on speculation” without “evidence or knowledge”.
Authorities in Wuhan initially tried to cover up the outbreak.
There were questions about the official tally of infections with the government repeatedly changing its counting criteria at the peak of the outbreak.
On Friday, authorities in the city admitted mistakes in counting its death toll and abruptly raised the figure by 50 percent.