BEIJING, Jan. 26 -- People having traveled from China's Wuhan are required to place themselves under medical observation at home for 14 days even without symptoms of pneumonia.

An official document asked county-level health departments to issue notices to alert those travelling from Wuhan, the hardest-hit city of the novel coronavirus (2019-nCoV) outbreak in central China, require them to report to community health stations and stay at home for a 14-day medical observation.

The document dated Friday was issued by an inter-agency mechanism on the prevention and control of the outbreak of pneumonia caused by the virus, which was headed by the National Health Commission.

It also asked for efforts to mobilize communities and village-level authorities to launch grid-based health management, tracking the health condition of the residents with the help of big data and the public.

Wuhan, a transportation hub with a population of over 10 million, had seen a massive amount of people coming and leaving before it on Thursday asked citizens not to leave the city, with many expressways closed, and flights and trains for outgoing passengers suspended.