Countries have started to evacuate their citizens from Wuchan, the Chinese city hardest-hit by coronavirus, which has now infected more people in China than SARS.
The number of confirmed cases jumped to 5,974, surpassing the 5,327 in mainland China during the SARS outbreak in 2002-2003.
The death toll rose to 132, which is still lower than the 348 people who were killed in China by SARS.
Scientists say there are still many critical questions to be answered about the new virus, including just how transmissible and severe it is.
A Japanese flight that brought back evacuees from the city of Wuhan included four passengers with coughs and fevers. Two were diagnosed with pneumonia.
The three men and one woman were taken to a Tokyo hospital in separate ambulances for treatment and further medical checks.
Another woman developed nausea at the airport and was also taken to hospital.
It was not immediately known whether they were infected with the new type of coronavirus, which first appeared in Wuhan in December.
Its symptoms, including cough and fever and in severe cases pneumonia, are similar to many other illnesses
China’s latest figures added 26 deaths, all but one in Hubei province and its capital, Wuhan.
The number of cases rose by 1,459 from the previous day, a smaller increase than the 1,771 new cases reported on Monday.
More than 50 infections have been confirmed abroad.
The United Arab Emirates, home to long-haul carriers Emirates and Etihad, reported its first cases on Wednesday in members of a family who had come from Wuhan, the state-run news agency reported.
It was not immediately clear how many family members were involved.
British Airways announced it was immediately suspending all flights to and from mainland China after the UK Government warned against unnecessary travel to the country.
The outbreak has also affected international sporting events, with the International Hockey Federation postponing Pro League games in China and qualifiers for the Tokyo Olympics scheduled in February in football, basketball and boxing being moved outside of the country.
With just 177 days before the summer games, Tokyo organisers are on edge over the outbreak’s possible knock-on effects.
In Australia, health officials said the Chinese women’s national soccer team was quarantined in Brisbane over concerns they had passed through Wuhan a week ago.
The team will be kept in isolation in a hotel until Wednesday next week. None of the group of 32 players and staff has shown symptoms.
Chartered planes carrying evacuees home to Japan and the US left Wuhan early on Wednesday as other countries planned similar evacuations from areas China has shut down to try to contain the virus.
The lockdown of 17 cities has trapped more than 50 million people in the most far-reaching disease control measures ever imposed.
Several countries have confirmed cases of the virus, with most of them being Chinese visitors, people who visited Wuhan or family members in close contact to the sick.
Japan’s six confirmed cases include a tour bus driver who drove visiting groups from Wuhan. Germany says four workers at an auto parts company possibly were infected when a colleague from Shanghai visited.
Australia and New Zealand were the latest countries planning evacuations.
Both countries also stepped up their travel advice to China, as did Britain.
Experts have feared travel during the Lunar New Year holiday would enable the further spread of the virus, and China expanded the holiday to keep people home, closing schools and offices to try to contain it.
Hong Kong was preparing to cut rail services from China at midnight.
Wuhan is building two hospitals in a matter of days to add 2,500 beds for treatment of patients with the virus.
The new virus is from the coronavirus family, which includes those that can cause the common cold as well as more serious illnesses such as SARS and MERS.
The source of the virus and the full extent of its spread are still unknown.
The World Health Organisation said most cases reported to date “have been milder, with around 20% of those infected experiencing severe illness.”