BEIJING/NEW YORK -- The Chinese city of Wuhan has shut down transit heading outbound and within its borders, as the death toll from a new respiratory virus originating there climbed to 17 people as of Wednesday, up from the nine fatalities previously reported.

According to China's Xinhua News Agency, the travel restrictions -- announced hours before they went into effect at 10 a.m. on Thursday -- involves an indefinite suspension of Wuhan's airports, train stations and intercity buses, as well as public transit within the city of 11 million people. The shutdown includes subways, buses and passenger ferries on the Yangtze River.

While travel in private cars has not been banned, the announcement said residents should remain in Wuhan "except under extraordinary circumstances."

City residents have been posting about the restrictions on the popular Weibo blog website, with comments ranging from complaints about the suspension of public transport to questions regarding access to streets and highways.

The coronavirus has infected 571 people in China, an increase from earlier reports of 543. China's National Health Commission confirmed cases in 25 provinces and provincial cities. Cases have also been reported in Thailand, Japan, South Korea, Taiwan, Hong Kong and the U.S.

The World Health Organization, which convened a meeting Wednesday to decide whether to declare the newly discovered coronavirus a global health emergency, postponed its decision to Thursday, citing the need for more information and deliberation.

"We need more information," WHO Director-General Tedros Adhanom Ghebreyesus told reporters after the meeting in Geneva. "The decision about whether or not to declare a public health emergency of international concern is one I take extremely seriously, and one I am only prepared to make with appropriate consideration of all the evidence."

He said that a WHO team is currently in China working with local experts and officials, and that the organization would have "much more to say" on Thursday.

Travelers wear face masks as they line up at turnstiles at a Nantong train station in Jiangsu Province on Jan. 22. © AP

The sharp rise in reported infections in China is credited partly to improved diagnostic techniques. Authorities reject accusations that the government is hiding the real numbers.

"We're singularly focused on disclosing information," said a senior National Health Commission official.

Wednesday marked the first time the commission held a news conference attended by a high-ranking Chinese official. Deputy Director Li Bin raised the concern that the virus could evolve into a more serious threat.

"The virus might mutate, and there is risk for further spreading," he said.

Li and the experts in attendance cited the likelihood of the coronavirus originating from wild animals sold at a seafood market in Wuhan. Many of the patients visited that particular market.

Wuhan will strictly monitor and control markets in the city, as well as impose tougher restrictions on trade in wild animals, Li said.

See also Wuhan lockdown and virus fears push Chinese to change travel plans

Health officials have classified the new coronavirus as a Class B infectious disease, a grade below Class A infections such as cholera. Authorities have avoided comparing the virulence with that of severe acute respiratory syndrome and Middle East respiratory syndrome, two illnesses also caused by coronaviruses.

China observes the one-week Lunar New Year holiday starting Friday. Travelers are expected to make roughly 3 billion trips over the 40 days surrounding the period.

Sichuan Province officials sent a notice to bus companies saying that trips to Wuhan should generally be suspended, according to local media. An Olympic boxing qualifier for Asia and Oceania, scheduled to be held in Wuhan in February, also was canceled.

Macro-analysts, citing China's SARS crisis 17 years ago, are bracing for the outbreak's short-term impact on the Chinese economy, which only recently got a reprieve via a partial U.S.-China trade deal.

"If the virus outbreak tracks the 2003 episode, we believe it will likely lead to significant downside risk in the next 1-2 quarters, especially in sectors such as tourism, catering services, [and] transportation," a group of JPMorgan analysts said in a Wednesday research note.

But the Chinese government has reacted "much faster this time" and appears better prepared, the report notes. The impact on China's full-year economic growth "will likely be limited." Fields such as online retail and entertainment, as well as delivery services, could remain a bright spot.