China has expanded its efforts to curb viral disease on Monday by extending New Year's holidays to keep the public at home and prevent the spread of infections as the death toll has increased to 81.
Chinese Premier Li Keqiang became the most senior Chinese leader to visit Wuhan since the city was struck by the outbreak of a deadly virus that has spread across the country and sparked global concern.
Thousands have been infected in China.
The youngest patient is a 9 month old girl in Beijing.
Closing transport out of Wuhan was a "very hard decision", added Zhou Xianwang, Wuhan's mayor, in an interview with state broadcaster CCTV on Monday.
There have been no reported deaths linked to the virus outside of China.
The U.S. consulate in Wuhan said it would arrange the evacuation of its diplomats and some American citizens on Tuesday. 5 cases in Hong Kong and 2 in Macao have been reported.
The nearby gambling hub of Macau, which has had at least one case of the flu-like virus, imposed a similar ban on those arriving from Hubei unless they can prove they are virus-free.
Mongolia is the second country to close its border with China, following North Korea.
In Wuhan, constructions workers raced to finish two prefab field hospitals within days.
In the city transformed into a ghost town, loudspeakers broadcast a message calling on residents to go to the hospital without delay if they do not feel well. Due to lack of supplies, they're forced to re-use disposable protective suits, which is potentially unsafe for contamination.
Images on social media showed hospital corridors packed with people seeking treatment.
USA orders evacuation of diplomats from Wuhan
Like the flu, the Wuhan coronavirus seems to have a greater impact on older adults and people with underlying health conditions. Authorities around the world have confirmed more than 1,200 coronavirus cases so far, including two in the United States.
Wuhan's mayor Zhou Xianwang said around five million people had left the stricken city during the new year travel rush in January, highlighting fears the virus could spread further. With nearly 20 million people being quarantined as authorities cancelled all flights and public transport, inter-city transport is also now prohibited to help people.
Earlier on Sunday, Zhou revealed that 5 million residents of Wuhan left the city before the lockdown was imposed on January 23.
Chinese health authorities say the new virus has infected 2,744 people and killed 80 as of midnight Sunday.
Authorities extended the weeklong Lunar New Year holiday by three days to February 2, in an attempt to slow the virus.
Typically hundreds of millions of people criss-cross China in jam-packed buses and trains during the Lunar New Year holiday, a time for family reunions.
The overall number of confirmed cases in China is 2,744 while more than 300 are critically ill.
"I'm getting more concerned everyday", Do Quang Duy, 32, a Vietnamese masters student in Wuhan, said. "The outbreak is expected to continue for some time".
The epidemic has revived memories of the SARS outbreak that originated in China and killed almost 800 as it spread around the world in 2002 and 2003.
All eyes will be on the World Health Organization this week, to see if it reverses the decision to hold off on classifying the Wuhan virus as a "public health emergency of global concern". Dr. Chuang Shuk-kwan, the head of Hong Kong's communicable disease branch, said the city's eight cases all have Hubei ties, so there was no no sign yet that it is spreading to Hong Kong's general population.
Tourism from China was already weakening even before the new virus forced much of the country into a standstill.
WHO Director-General Tedros Adhanom Ghebreyesus had arrived in China and would meet officials working on the response, his agency said. The outbreak will affect all the China-based companies but the biggest impact will be on travel, hotels, and restaurants, according to forecasters.
Two of Hong Kong's most popular tourist attractions, Hong Kong Disneyland and Ocean Park, have been closed.