The World Health Organization has declared that the new coronavirus epidemic is at a "decisive point" as countries across the globe battled to contain the deadly outbreak.
Saudi Arabia has banned pilgrims from visiting Islam's holiest sites as the number of deaths jumped in neighbouring Iran, while Japan and Iraq ordered the closure of schools.
Alarm is growing as China is no longer the only breeding ground for Covid-19, with other countries including South Korea and Italy becoming hotbeds of infection, raising fears of a pandemic.
"We're at a decisive point," WHO chief Tedros Adhanom Ghebreyesus told a press conference in Geneva. "If you act aggressively now, you can contain this virus, you can prevent people getting sick, you can save lives."
The virus has already killed more than 2,760 people, mostly in China - where it first emerged in December - and infected more than 81,000 in over 45 countries.
But there are now more daily cases being recorded outside China, raising fears that poor countries with weak health infrastructures would not be able to cope.
"It's what's happening in the rest of the world that's now our greatest concern," Dr Tedros said.
World financial markets have plunged on fears that widespread lockdowns could hamper business activity and dent global growth, while sports matches and festivals have been cancelled to try to stem infections.
The EU said it was bracing for an economic hit, with tourism already feeling the pinch and supply chains reliant on China also being affected.
French President Emmanuel Macron said France, the world's most visited country which has recorded two deaths, was preparing for a jump in cases.
"We are facing a crisis, an epidemic that is coming," he said.
With Covid-19 spreading in the Middle East, Saudi Arabia suspended visas for visits to Islam's holiest sites for the "umrah" pilgrimage, an unprecedented move, raising questions over the hajj which starts in July.
The kingdom - which hosts millions of pilgrims every year - said it was also suspending visas for tourists visiting from countries where the virus is a "danger".
Neighbouring Iran reported seven new deaths over 24 hours, taking the overall toll to 26, the highest outside China.
Tehran also imposed domestic travel restrictions for confirmed or suspected cases and slapped curbs on visits to major Muslim pilgrimage sites, while Iran's neighbours have shut their borders.
The first cases in Afghanistan, Pakistan and Estonia involved people who had been in Iran.
In Japan, schools were ordered to close for several weeks, after the government struggled to deal with the fallout of infections from a cruise ship it quarantined off the coast.
Japan has seen at least 186 cases of infection among the general population, with four deaths.
Worryingly, one woman was found to be positive again after initially contracting the virus, then being released from hospital after treatment and a negative test.
Several governments have also advised against travel to Italy - Europe's epicentre with 528 cases and 14 deaths.
In Latin America's first case, a 61-year-old patient in Brazil had travelled to Italy. Other countries including Algeria, Denmark, Romania and Spain have also reported infections linked to Italy.
But Rome hit back, with Foreign Minister Luigi Di Maio slamming "false reports" abroad about panic, cities in lockdown and runs on supermarkets, saying they were "doing more damage than the risk of an epidemic".
The US and South Korean militaries announced the postponement of joint exercises planned for this spring after Seoul declared its highest "severe" alert level over the virus which has claimed 12 lives out of almost 1,600 cases, the highest number outside China.
Even China itself - which sealed off an entire province and shut down cities across the country - is now worried about importing cases and ordered people arriving in Beijing from affected countries to go into 14-day self-quarantine.
China reported 29 more deaths Thursday - its lowest daily tally since January - and 433 new cases.
But US President Donald Trump has played down fears of a major outbreak in the United States.
"I think that there's a chance that it could get worse, a chance it could get fairly substantially worse, but nothing's inevitable," Mr Trump said.
US public health officials confirmed a coronavirus case in California, the first of unknown origin out of about 60 cases, and have told Americans to be ready to cancel mass gatherings and work from home.
The virus is believed to have originated in a market in the central Chinese city of Wuhan, where it is suspected of having hopped from animal to human.
Hubei officials have been accused of initially covering up the outbreak and silencing a whistleblowing doctor who later died from the disease.
Dr Tedros said all countries should ensure their health systems were prepared.
"We are actually in a very delicate situation in which the outbreak can go in any direction based on how we handle it."
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