South Korea went on high alert Sunday following a sharp jump in coronavirus cases, and Italy and Iran took their own drastic containment steps as an epidemic that has killed nearly 2,500 people in China continued a relentless global expansion.
The World Health Organization (WHO) also warned that Africa's poor health systems left it vulnerable to the COVID-19 disease, which spilled out of China to more than 25 countries.
South Korea is raising the nation's alert to its "highest" level, President Moon Jae-in said on Sunday after the number of infections nearly tripled over the weekend to 556.
Led by an outbreak cluster in a religious sect in the southern city of Daegu, South Korea now has the most infections outside of China apart from the Diamond Princess cruise ship docked in Japan, which has seen more than 600.
"The next few days will be crucial," Moon said following a government meeting on the virus.
"The government will raise the alert level to the highest level according to experts' recommendations."
Moon did not specify what those measures may include.
South Korea reported 123 new cases and two deaths on Sunday, taking the countrywide toll of fatalities to four.
More than 300 cases have been linked to the Shincheonji Church of Jesus sect in Daegu -- whose founder claims the mantle of Jesus Christ and vows to take 144,000 people with him to heaven on judgement day.
Some 9,300 Shincheonji members have either been quarantined or asked to stay at home, according to the Korean Centers for Disease Control and Prevention.
More than 1,240 have reported symptoms.
Elsewhere, Italy and Iran began introducing the sort of containment measures previously seen only in China, which has put tens of millions of people under quarantine lockdown in the epicentre province of Hubei.
More than 50,000 people in about a dozen northern Italian towns near the business hub of Milan were urged by authorities to stay home, while shops and schools were shuttered.
With dozens of cases, Italy on Friday became the first European country to report one of its nationals had died from the virus, followed by a second death on Saturday.
Both were elderly.
The government was weighing "extraordinary measures" to halt further infections, Italian Prime Minister Giuseppe Conte said.
China reported another 97 deaths in its daily update Sunday, taking its total to 2,442, plus 648 new infections. Nearly 80,000 people have been infected worldwide, the vast majority in China.
China's outbreak remains concentrated in the locked-down city of Wuhan, where the virus is believed to have emanated from a live animal market in December.
The city was locked down exactly one month ago as of Sunday, followed by surrounding areas.
China's infection rate has slowed from early in the epidemic, but Chinese flip-flopping over counting methods has sowed confusion over its data.
There also was growing concern over the difficulty of detecting the virus.
Japan on Sunday confirmed that a woman who tested negative and disembarked from the Diamond Princess later tested positive. Similar instances have been reported elsewhere.
Japan has been criticised over its handling of the cruise ship.
Many passengers were allowed to disembark without being properly tested or despite having close contact with infected people.
More than 1,000 crew remain on board and are expected to serve a 14-day quarantine.
Fears for Africa
Iran ordered the closure of schools, universities and cultural centres across 14 provinces from Sunday following five deaths in the Islamic Republic -- the most outside East Asia and the first in the Middle East.
Iran's outbreak surfaced Wednesday and quickly grew to 28 confirmed infections.
"The concern is ... that we have seen ... a very rapid increase (in Iran) in a matter of a few days," said Sylvie Briand, director of the WHO's global infectious hazard preparedness department.
Iraq on Thursday clamped down on travel to and from Iran, and flag carrier Kuwait Airways has suspended flights to the country.
Although Egypt is the only African country with a confirmed case, the WHO warned that the continent was vulnerable, urging more African Union cooperation.
WHO chief Tedros Adhanom Ghebreyesus said necessary treatment tools such as respiratory support machines were "in short supply in many African countries and that's a cause for concern".
The US State Department said anxiety was being stoked by a coordinated effort by thousands of Russia-linked social media accounts spreading conspiracy theories that the outbreak was a US-orchestrated ploy to damage China, officials said.
Russia's foreign ministry dismissed the allegation as "deliberately false".