The toll from a new virus in China rose to six deaths and more than 300 cases on Tuesday as millions of Chinese prepared to travel for the Lunar New Year, heightening contagion risks.
Many in China scrambled to buy face masks to protect themselves from the previously unknown, flu-like coronavirus infection and airports around the world tightened screening.
The outbreak, which began in the central Chinese city of Wuhan, also worried financial markets as investors recalled the economic damage from China's Severe Acute Respiratory Syndrome (SARS) epidemic in 2002/2003 that it initially covered up.
The SARS coronavirus outbreak killed nearly 800 people then.
"We'll stay at home during the holiday. I'm scared as I remember SARS very well," said Zhang Xinyuan, who had been bound from Beijing for the Thai resort of Phuket before she and her husband decided to cancel their air tickets.
Authorities have confirmed more than 300 cases of the new coronavirus in China, mostly in Wuhan, a provincial capital and transportation hub, where it may have come from a seafood market.
Symptoms include fever, coughing and difficulty in breathing, and the viral infection can cause pneumonia.
Wuhan mayor Zhou Xianwang told Chinese state television on Tuesday six people had died in his city. The disease was spreading further around other parts of China, however, including five cases in the national capital Beijing.
Fifteen medical personnel are among those infected.
Abroad, Thailand has reported two cases and South Korea one, all involving Chinese from Wuhan. Japan and Taiwan also confirmed one case each, both nationals who had been to Wuhan.
The World Health Organization (WHO) will hold a meeting on Wednesday to consider whether the outbreak is an international public health emergency.
"Information about newly reported infections suggest there may now be sustained human-to-human transmission," said WHO's regional director for the western Pacific, Takeshi Kasai.
Taiwan, the self-ruled island that China claims as its own, set up an epidemic response centre. More than 1,000 beds were prepared in isolation wards in case the virus spreads further.
North Korea was to temporarily ban foreign tourists, who are mainly Chinese, a foreign tour operator said.
The scare stirred risk aversion on global markets, with Asia particularly hit.
Hong Kong, which suffered badly during the SARS outbreak, saw its index fall 2.8%. Japan's Nikkei lost 0.9% and Shanghai blue chips 1.7%, with airlines under pressure.
In Europe, shares of luxury goods makers, which have large exposure to China, were among those declining the most.
China's yuan fell almost 0.7% in offshore trading to 6.9126 per dollar. Onshore, it dipped to its lowest in over a week at 6.9094.
Though the origin of the virus has yet to be identified, WHO said the primary source was probably animal. Chinese officials have linked the outbreak to Wuhan's seafood market.
"The outbreak of a SARS-like coronavirus in Wuhan is developing into a major potential economic risk to the Asia-Pacific region now that there is medical evidence of human-to-human transmission," said Rajiv Biswas, Asia Pacific Chief Economist for IHS Markit.
So far, the WHO has not recommended trade or travel restrictions but they may be discussed on Wednesday. China's National Health Commission is also scheduled to give an update at a press briefing at 10 a.m. (0200 GMT) on Wednesday.
Airports in the United States, Australia and across Asia have begun extra screening for passengers from Wuhan.
In the city itself, officials have been using infrared thermometers to screen passengers at airports, railway stations and other passenger terminals since Jan. 14.
The Lunar New Year is a major holiday for Chinese, many of whom travel to join family or have a foreign holiday.
Long lines formed to buy face masks in cities. Some online vendors limited sales of masks and hand sanitizers as demand surged.
Shanghai city's market regulator warned it would punish speculators hoarding masks or other products used for preventing infectious diseases, according to the Shanghai Observer web publication.
Chinese travel booking platforms from Trip.com to Alibaba Group's Fliggy said they would offer free cancellations on bookings made for Wuhan, while South Korean budget airline T'way Air postponed its launch of a new route to the city.
Zhong Nanshan, head of the National Health Commission's team investigating the outbreak, sought to ease alarm, saying in footage shown by state television there was no danger of a repeat of the SARS epidemic so long as precautions were taken.
South Korean budget airline T'way Air has postponed Tuesday's scheduled launch of a new route to the Chinese city of Wuhan because of rising concern over the spread of a new coronavirus, a company official said.
On Monday South Korea reported its first confirmed case of the virus from a 35-year-old Chinese national who flew from Wuhan to Seoul on Sunday.
T'way had been set for the first of its twice-a-week flights from the South Korean main hub of Incheon to Wuhan at 1020 p.m. (1320 GMT) but canceled its plans because of the outbreak, the company official said.
"It was an inevitable decision because of the situation there," the official told Reuters, adding that it would continue to monitor developments.
The move came amid spiraling fears over the virus, which could be spread through human contact, with millions of Asians traveling for the Lunar New Year holiday this week. In China, the number of confirmed cases rose to 291 on Monday.
An official at Korean Air Lines, the only other South Korean airline operating direct flights to Wuhan, said the company had no plans to suspend its route, which operates four times a week, but will waive ticket cancellation fees for passengers traveling to the city.
South Korea's Centres for Disease Control and Prevention on Tuesday warned tourists against contact with animals and people showing respiratory symptoms and market visits in China.
President Moon Jae-in instructed local authorities to step up prevention efforts, with many South Koreans living in China expected to return home and some 32 million traveling around the country for the holiday until next week.