Meta said Facebook removed Wilson Edwards account in August and has since removed 524 Facebook accounts, 20 Pages, four Groups, and 86 Instagram accounts.
Facebook owner Meta Platforms said on Wednesday it had removed accounts used by an influence operation originating in China that promoted claims of a fake "Swiss biologist" saying the United States was interfering in the search for COVID-19's origins.
Meta said in a report the social media campaign was "largely unsuccessful" and targeted English-speaking audiences in the United States and Britain and Chinese-speaking audiences in Taiwan, Hong Kong, and Tibet.
Claims by "Swiss biologist" Wilson Edwards were widely quoted by Chinese state media in July. In August, several Chinese newspapers removed comments and deleted articles quoting him after the Swiss embassy in Beijing said it had found no evidence of him as a Swiss citizen.
Meta said Facebook removed the Wilson Edwards account in August and has since removed 524 Facebook accounts, 20 Pages, four Groups and 86 Instagram accounts as part of its investigation. Such removals also take down content that these entities have posted.
"We...were able to link the activity to individuals in mainland China, including employees of a particular company in China, the Sichuan Silence Information Technology Company Limited, as well as some individuals associated with Chinese state infrastructure companies around the world," Meta's head of global threat disruption David Agranovich told Reuters.
Sichuan Silence Information Technology Co did not immediately respond to a request for comment. The Chinese foreign ministry and internet regulator Cyberspace Administration of China also did not immediately respond to requests for comment.
Meta said it had not found any connection between Sichuan Silence Information Technology and the Chinese government.
Silence Information's website describes itself as a network and information security company that provides network security services to China's Ministry of Public Security activities and China's CNCERT, the key coordination team for China's cybersecurity emergency response.
On July 24, 10 hours after its creation, the "Wilson Edwards" Facebook account uploaded a post saying he had been informed the United States was seeking to discredit the qualifications of World Health Organization scientists working with China to probe the origins of COVID-19.
Meta said the account's operators used virtual private network (VPN) infrastructure to conceal its origin and made efforts to give Edwards a rounded personality.
The persona's original post was initially shared and liked by fake Facebook accounts, and later forwarded by authentic users, most of which belonged to employees of Chinese state infrastructure companies in over 20 countries, Meta said.
"This is the first time we have observed an operation that included a coordinated cluster of state employees to amplify itself in this way," the report said. Meta said it did not find evidence that the network gained any traction among authentic communities.
China's state-run media, from China Daily to TV news service CGTN, cited the July post widely as evidence that US President Joe Biden's administration was politicising the WHO. The administration had said the joint WHO-China investigation lacked transparency.
The origin of the SARS-CoV-2 virus that causes COVID-19 remains a mystery and a source of tension between China, the United States and other countries.