The World Health Organization has declared the new coronavirus an international emergency but has held off on recommending restrictions on the movement of people. The UN health agency praised "China's aggressive containment effort".
The World Health Organization (WHO), which faced criticism for initially downplaying the virus threat, revised its risk assessment after crisis talks in Geneva.
"Our greatest concern is the potential for the virus to spread to countries with weaker health systems," said WHO chief Tedros Adhanom Ghebreyesus.
"We must all act together now to limit further spread... We can only stop it together."
Tedros said travel and trade restrictions involving China were unnecessary, but authorities and businesses around the world have been taking matters into their own hands.
Germany, Britain and other countries have issued warnings about travel to China, major airlines have suspended or reduced flights to the country, and Mongolia has halted cross-border traffic with its huge southern neighbour.
Russia also sealed its remote far-eastern border with China as a precaution.
Some countries have banned entry for travellers from Wuhan, the central Chinese city where the virus first surfaced, while Italy and Israel on Thursday barred all flight connections with China.
The United States told its citizens not to travel to China in the first major response to the WHO's declaration of a global emergency. Chinese authorities on Friday increased the toll to 213 dead and nearly 10,000 infections.
The State Department in Washington raised it warning alert to the highest level, telling US citizens not to travel to China because of the epidemic which has now spread to more than 20 nations.