Chinese health authorities announced Wednesday that 440 confirmed cases of pneumonia caused by the novel coronavirus (2019-nCoV) had been reported in 13 provincial-level regions in the country by the end of Tuesday.
The cases had resulted in nine deaths, all in central China's Hubei Province, said Li Bin, deputy director of the National Health Commission (NHC), at a press conference.
Altogether 149 new confirmed cases were reported Tuesday, Li added.
Overseas, one case has been confirmed in Japan, three in Thailand, and one in the Republic of Korea.
A total of 2,197 close contacts have been traced, figures from the commission show. Among them, 1,394 are under medical observation while 765 others have been discharged.
The cases of infection have been on the rise recently, which is possibly due to improved diagnostic methods and advanced reagents for confirming the new coronavirus-related pneumonia, Li said.
Experts also said that respiratory transmission is the main path of contagion and the virus is likely to mutate, which will increase the risks of it spreading.
The commission has been releasing daily reports on the number of confirmed cases and suspected cases since Jan. 20.
Experts called for being alert as there will be increased population mobility amid Chinese Lunar New Year.
Strict measures have been taken to prevent the spread of the virus. A total of 15 thermal detectors have been set up in the Wuhan Tianhe International Airport, and 20 thermal detectors have been installed in three major railway stations of the city.
The city will also strictly monitor and control the farmer's markets as well as the supermarkets and restaurants, as well as toughen crackdowns on wild animal trade, Li said.
He added that public gatherings will be restricted, and unnecessary entry and exit trips to Wuhan will be called off.
"We should be strictly on guard against the pneumonia situation spreading outside Wuhan," Li said.
Gao Fu, head of the Chinese Center for Disease Control and Prevention, said there is no evidence so far showing that a super-spreader, or a highly contagious virus carrier, has emerged.
He added that, based on current evidence, the virus was originated from wild animals sold at a seafood market of Wuhan.
In accordance with laws and regulations, quarantine measures are being taken on entry and exit ports, Li Bin said.
As of Jan. 20, China had shared information with the World Health Organization (WHO), related countries and local authorities in Hong Kong, Macao and Taiwan on 15 occasions, Li noted.
The NHC has organized four meetings with experts from the WHO and invited them to Wuhan for first-hand information on the outbreak, according to Li.
"We are maintaining close communications with our counterparts in Thailand, Japan, the Republic of Korea, the United States and other countries and their respective embassies in China, sharing the latest information while helping with diagnostic verification," Li said.
The NHC has provided free diagnostic kits to health authorities in Hong Kong and Macao on request, he added.