Scientists in China raised the alarm about coronavirus in December but were told by government officials to suppress the evidence, a report has claimed.
In December a number of sick patients in Wuhan were tested by genomics companies, who noticed similarities between their illnesses and SARS, as reported by the NY Post.
Researchers told Beijing about their findings, but were told to keep quiet by China's National Health Commission.
It is understood that local officials did not tell representatives from the US Centers for Disease Control and Prevention when they visited Wuhan on January 8 about the outbreak.
A man wearing a facemask to protect against the COVID-19 coronavirus looks on at the Beihai park in Beijing
Shortly afterwards on January 20, China launched a massive effort to contain the virus, shutting down Wuhan.
It comes as Donald Trump banned travel to Iran after America reported its first death from the virus, also known as Covid-19.
The US president added that he was considering additional restrictions, including closing the border with Mexico in response to the outbreak.
WHO's Director General Dr Tedros Adhanom Ghebreyesus told his half a million Twitter followers yesterday: 'If you are 60+, or have an underlying condition like cardiovascular disease, a respiratory condition or diabetes, you have a higher risk of developing severe #COVID19.
'Try to avoid crowded areas, or places where you might interact with people who are sick.'
While infection is far more likely to cause severe illness in the elderly, the advice also applies to people of all ages who have serious health conditions (pictured, army soldiers wearing protective suits spraying disinfectant in Daegu, South Korea)
In Australia, a 78-year-old man who contracted coronavirus on board the Diamond Princess cruise ship off Japan became the first Australian to die of the disease.
Emerging clusters in Italy and in Iran, which has had 43 deaths and 593 cases confirmed, have led to infections of people in other countries.
Iran has the highest death toll outside China, and health officials urged people not to attend funerals, as mass gatherings could help spread the virus.
Earlier on Saturday, Bahrain threatened to prosecute travellers who came from Iran and had not been tested. The island nation has been hard-hit and shut down flights to halt the spread, and all its cases link back to Iran.