Fears are growing that the coronavirus outbreak could become a pandemic as new cases are reported around the world.
Most infections are in China but other countries including South Korea, Italy and Iran are battling to contain the virus, which causes the respiratory disease Covid-19.
A pandemic is declared when an infectious disease threatens different parts of the world simultaneously.
No vaccine is available so far to prevent the new coronavirus.
About 77,000 people in China, where the virus emerged last year, have been infected and nearly 2,600 have died.
More than 1,200 cases have been confirmed in 26 other countries and there have been more than 20 deaths. Italy reported its fourth death on Monday.
The proportion of infected patients dying from Covid-19 appears to be between 1% and 2%, although the World Health Organization (WHO) cautions that the mortality rate is not known yet.
On Monday Iraq, Afghanistan, Kuwait and Bahrain reported their first cases, all involving people who had come from Iran.
WHO chief Tedros Adhanom Ghebreyesus had warned that the window of opportunity to contain the virus was “narrowing”.
Paul Hunter, professor of health protection at the University of East Anglia in the UK, echoed his fears, saying the spike in cases outside China was “extremely concerning”.
“The tipping point after which our ability to prevent a global pandemic seems a lot closer after the past 24 hours,” he said on Monday.
WHO spokeswoman Margaret Harris told the BBC that the situation was not being seen as a pandemic at the moment because countries were managing to prevent the virus spreading too far.
“If countries took no measures at all we would have seen way, way, way more cases,” she said. “That’s what we mean by containment.”