One of the world's top epidemiologists admits he first heard about the pandemic outbreak in Wuhan more than two weeks before it was disclosed to global health bodies, Daily Mail reported.
The revelation by Ian Lipkin, a professor at Columbia University honoured by China for work on the first Sars epidemic earlier this century, undermines the official Beijing narrative on the origins, the report said.
Lipkin told a documentary by director Spike Lee that he learned of "the new outbreak" on December 15, even repeating the date for clarification.
Yet China claims there were only five known patients before that time in Wuhan - a city of 11 million people - with the earliest confirmed case of a patient with the novel coronavirus supposedly cropping up just one week earlier.
The World Health Organisation was not tipped off for another 16 days after Taiwan raised the alarm.
This delay - along with China's cover-up of human transmission - allowed the virus to spread rapidly, with disastrous consequences, the report added.
Lipkin's intervention erodes China's efforts to mask the truth about the pandemic's emergence.
Beijing has hidden data, silenced doctors, jailed journalists, blamed other nations and resisted unfettered inquiries by global health bodies, Daily Mail said.
The US scientist, who has worked in China for almost two decades, also told a Columbia University medical centre video recording that he first heard about the outbreak "in the middle of December 2019".
Lipkin said he had been "tracking" the disease with "my friends there" at the Centre for Disease Control "and in the national government", before visiting the country to investigate the following month.
He also told a podcast he was tipped off by his Chinese research partner Lu Jiahai, a public health professor at a Guangzhou university who has said the epidemic could have been prevented if warning systems had functioned properly.