China said the number of infections from a new virus surpassed 20,000.
Hong Kong on Tuesday reported its first death from the illness, a man who had travelled from the mainland city of Wuhan that has been the epicentre of the outbreak.
The semi-autonomous territory shut almost all of its land and sea border crossings with the mainland at midnight after medical workers began a strike demanding the border be closed completely. More than 2,000 hospital workers went on strike Monday, and their union has threatened a bigger walkout Tuesday.
Hong Kong was hit hard by SARS, or severe acute respiratory syndrome, in 2002-03, an illness from the same family of viruses as the current outbreak and which many believe was intensified by official Chinese secrecy and obfuscation.
Singapore on Tuesday announced the first local transmissions.
The Ministry of Health said it had found six additional cases, four of them involving human-to-human transmission in Singapore, bringing the total infections to 24 in the city-state.
"Though four of these cases constitute a local transmission cluster, there is as yet no evidence of widespread sustained community transmission in Singapore," the ministry said in a statement.
Global health emergency
The World Health Organization last week declared the virus a global health emergency and expressed concern about how it was spreading in other countries, beyond those who were Chinese or who had travelled in Hubei recently.
On Tuesday, the Korea Centers for Disease Control and Prevention said a 42-year-old South Korean woman tested positive for the virus, days after she returned from a trip to Thailand with chills and other symptoms.
It is South Korea's 16th case. Thailand has confirmed 19 cases, mostly Chinese tourists but also in a Thai taxi driver.
A passenger on a Japanese-operated cruise ship tested positive after leaving the vessel while it was in Hong Kong, and Japanese officials were considering a quarantine of the more than 3,000 people on board.
The Diamond Princess returned to Yokohama after making port calls in Vietnam, Taiwan and Okinawa.
The ship's captain said Hong Kong's health authorities notified the ship about the passenger's infection on Saturday, according to a recording of the announcement tweeted by a passenger. The patient is recovering, and his travelling companions so far have not been infected, the captain's announcement said.
“I wish we were informed as soon as they found out, then I could have worn a mask or washed hands more carefully," the passenger said.
“I was in Hong Kong nine days ago and it seems to be too late now.”
Other countries are continuing evacuations and restricting the entry of Chinese or people who have recently travelled in the country.
A plane carrying Malaysians from Wuhan, the capital of Hubei province where the illness has been concentrated, arrived in Kuala Lumpur on Tuesday morning, and the 133 people on board were to be screened and quarantined for 14 days, the maximum incubation period for the virus.
Vietnam to quarantine 950 people
Vietnam has assigned the military to quarantine 950 Vietnamese returning from China, where the coronavirus epidemic has killed more than 420 people, state media reported on Tuesday.
The 950 people will be isolated at two military camps outside Hanoi for at least 14 days, reported the official Voice of Vietnam Radio.
Taiwan imposes travel restrictions
Taiwan's Foreign Ministry said the island will deny entry to all foreign nationals who had been to China during the past 14 days starting from Friday due to the increasing threat from the coronavirus epidemic.
The new incoming travel ban includes all foreign nationals who have been in China since February 7, Taiwan's foreign ministry said in a statement. It extends an existing ban on visitors from China but does not include visitors from Hong Kong and Macau.
PLA medics arrive in Wuhan
As medical workers and patients arrived at the new virus hospital in Wuhan, President Xi Jinping said, “We have launched a people's war of prevention of the epidemic”.
Xi presided over a special meeting of the top Communist Party body for the second time since the crisis started, telling the Politburo standing committee on Monday that the country must race against time to curb the spread of the virus. He also said those who neglect their duties will be punished, state broadcaster CCTV reported.
Medical teams from the People's Liberation Army were arriving in Wuhan to relieve overwhelmed health workers and to staff the new 1,000-bed hospital. It was built in just 10 days, its prefabricated wards equipped with state-of-the-art medical equipment and ventilation systems.
A 1,500-bed hospital also specially built for patients infected with the new virus is due to open within days.
With no end to the outbreak in sight, authorities in Hubei and elsewhere extended the Lunar New Year holiday break, due to end this week, well into February to try to keep people at home and reduce the spread of the virus.
All Hubei schools are postponing the start of the new semester until further notice.
Chinese scientists said they have more evidence the virus, which was first detected in Wuhan in December, likely originated in bats. In a study published in the journal Nature, Shi Zhen-Li and colleagues at the Wuhan Institute of Virology reported that genome sequences from seven patients were 96 percent identical to a bat coronavirus.
SARS is also believed to have originated in bats, although it jumped to civet cats before infecting people. Scientists suspect the latest outbreak began at a seafood market in Wuhan where wild animals were on sale and in contact with people.