The Health Ministry issued a travel warning Monday on visiting the central Chinese city of Wuhan due to the outbreak of a mysterious respiratory disease in the city that has already killed three people.

Health Ministry Epidemiology Division Manager Dr. Emilia Anis said in a video message that those traveling to the city should “avoid contact with animals, dead or alive, and avoid spending time in animal markets.”

“It is also advisable to avoid close contact with people suffering from respiratory disease and to maintain hygiene,” she added.

Anis said the ministry is in contact with the World Health Organization, the US Centers for Disease Control, and the European Centre for Disease Prevention and Control to get an accurate situations update.

The outbreak is believed to have started late last month when people picked it up at a fresh food market in Wuhan.

Wuhan health authorities said Monday an additional 136 cases have been confirmed in the city, raising the total to 198.

The ministry warning came as a top Chinese expert on infectious diseases confirmed human-to-human transmission of the SARS-like virus that has spread across the country and reached three other Asian nations, state media reported.

Zhong Nanshan, a renowned scientist at the national health commission who helped expose the scale of the 2003 outbreak of Severe Acute Respiratory Syndrome (SARS), said human-to-human transmission is “affirmative,” said state broadcaster CCTV.

“Currently, it can be said it is affirmative that there is the phenomenon of human-to-human transmission,” he said in an interview with CCTV.

The new coronavirus strain has caused alarm because of its connection to SARS, which killed nearly 650 people across mainland China and Hong Kong in 2002-2003.

Currently, the total number of people diagnosed with the Wuhan disease in China is 218, while Thailand, Japan, and South Korea have also reported cases.

Zhong said patients can contract the virus without having visited Wuhan.

In southern Guangdong province, two patients were infected by family members who visited Wuhan, he told CCTV.

The spread of the viral pneumonia comes as the country enters its busiest travel period, when millions board trains and planes for the Lunar New Year holidays.

China’s leader called on the government to take every possible step to combat the outbreak.

“The recent outbreak of novel coronavirus pneumonia in Wuhan and other places must be taken seriously,” President Xi Jinping said in his first public statement on the crisis. “Party committees, governments and relevant departments at all levels should put people’s lives and health first.”

Xi’s remarks were reported by state broadcaster CCTV.

At least a half-dozen countries in Asia and three US airports have started screening incoming airline passengers from central China. The list includes Thailand and Japan, which have together reported three cases of the disease in people who had come from Wuhan.

The virus causing the current outbreak is different from those previously identified, Chinese scientists said earlier this month. Initial symptoms of the novel coronavirus include fever, cough, tightness of the chest, and shortness of breath.