The worst-hit countries are intensifying their efforts to contain the deadly coronavirus as the number of cases globally surpassed 80,000.
In South Korea, infections have risen again, taking the total to 977. Americans have been warned against all but essential travel to the nation.
Italy and Iran are both battling to contain outbreaks of the virus.
In Japan shares slumped on Tuesday, reacting to a global plunge on Monday sparked by fear of further outbreaks.
Wall Street and London had both suffered big drops.
The World Health Organization said on Monday the world should do more to prepare for a possible pandemic - a situation where an infectious disease spreads easily between people in many countries.
The WHO said it was too early to label the outbreak as such, but countries should be "in a phase of preparedness".
Coronavirus: Could it become a pandemic?
A visual guide to the outbreak
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More cases of the virus, which causes respiratory disease Covid-19, continue to emerge, with the vast majority still in China. The proportion of infected people who die appears to be between 1% and 2%, although the WHO cautions that the mortality rate is not known yet.
