The United States on Friday summoned China’s ambassador after a top government official tweeted a conspiracy theory suggesting that the US Army may have started the coronavirus pandemic, AFP reported.

China’s Foreign Ministry spokesperson Zhao Lijian on Thursday claimed that it might be the US Army that brought the deadly coronavirus to China. Zhao’s tweet was accompanied by a video of a US health official saying that some of the people thought to have died of influenza were posthumously diagnosed as having had coronavirus or COVID-19.

Zhao also posted a link to an article on the origin of coronavirus from a website named Global Research, known for publishing conspiracy theories about the 9/11 attacks.

David Stilwell, the top US diplomat for Asia, issued a “stern representation” to Chinese Ambassador Cui Tiankai over Zhao’s tweet.

A US State Department official castigated Zhao for his comments, saying that spreading conspiracy theories is “dangerous and ridiculous”, according to AFP. “We wanted to put the government on notice we won’t tolerate it, for the good of the Chinese people and the world,” he said. “China is seeking to deflect criticism for its role in starting a global pandemic and not telling the world.”

With cases of coronavirus falling in China and rising abroad, Beijing is now rejecting the wide opinion that the outbreak began in Wuhan, a city in Hubei province. Chinese authorities have also reacted strongly to the outbreak being referred to as the ‘Wuhan virus’.

The coronavirus outbreak is believed to have originated in a seafood market in Wuhan. More than 80,000 cases of coronavirus were reported from China. Over 3,000 people have died. On Thursday, China declared that the peak of the coronavirus outbreak had passed in the country after new cases in Hubei fell to single digits for the first time.

Coronavirus has spread to over 100 countries, infecting 1.27 lakh people and killing more than 5,000. The World Health Organization on Wednesday declared the outbreak a pandemic.