The Covid-19 virus may have originated from humans, CNN quoted a Chinese scientist as saying.
His statements came during a press conference held by the Chinese State Council regarding research into the origin of the virus.
"The genetic sequences of viral samples taken from the Huanan Seafood Market in Wuhan – thought to be the ground zero site of the pandemic – were “almost identical” to those of patients infected with the coronavirus, suggesting that Covid-19 may have originated from humans," said Tong Yigang of the Beijing University of Chemical Technology.
Tong said more than 1,300 environmental and frozen animal samples had been taken at the market between January 2020 and March 2020, and researchers had isolated three strains of virus from the environmental samples.
He also said there was not yet sufficient evidence to back up recent studies that had suggested racoon dogs were the origin of the Covid-19 virus.
Earlier in March, Reuters reported international researchers saying that data from the early days of the COVID pandemic, briefly uploaded to a database by Chinese scientists, gives information on its origins, including suggesting a role for raccoon dogs in the coronavirus reaching humans.
The virus was first identified in the Chinese city of Wuhan in December 2019, with many suspecting a live animal market to be involved, before spreading round the world and killing nearly 7 million people to date.
International researchers published a pre-print report based on their interpretation of the data in March, after leaks of their findings in the media last week and a meeting with the World Health Organization involving both the Chinese and international scientists. The WHO has urged China to release more information.
The data comprised new sequences of the SARS-CoV-2 virus and additional genomic data based on samples taken from the Huanan market in Wuhan in 2020, according to the international researchers who accessed it.
The sequences showed that raccoon dogs and other animals susceptible to the coronavirus were present in the market and may have been infected, providing a new clue in the chain of transmission that eventually reached humans, they said.
"This adds to the body of evidence identifying the Huanan market as the spillover location of Sars-CoV-2 and the epicentre of the COVID-19 pandemic," said the report.
The data from the Chinese Center for Disease Control and Prevention (CDC) had been uploaded to GISAID, the global pathogen database, ready for it to be included in a scientific paper set to be published in a major journal.
As of March 11, it was no longer accessible on the database, where it was found by the international scientists, their report said. GISAID said in a statement it was "temporarily invisible" while it was being updated ahead of the paper's publication, in line with normal practice.
The report was written by authors including the University of Arizona's Michael Worobey, Kristian Andersen of Scripps Research in La Jolla, California, and Florence Debarre at the Sorbonne University in Paris, France, who accessed the data.
They say they have broken no rules in accessing the data.
It was not immediately clear whether the release of their report would have any immediate impact on the data becoming accessible again, or the publication of the paper by the Chinese scientists.
The team also called for more information to be shared.
"Other raw sequencing data from environmental samples from the Huanan market exist and could contain further clues," Debarre told Reuters.