China raised its emergency warning to its second-highest level and cancelled more than 60 per cent of the flights to Beijing on Wednesday amid a new coronavirus outbreak in the capital.
It was a sharp pullback for the nation that declared victory over Covid-19 in March and a message to the rest of the world about how tenacious the virus really is.
New infections spiked in India, Iran and US states including Florida, Texas and Arizona as authorities struggled to balance restarting economic activity without accelerating the pandemic.
European nations, which embarked on a wide-scale reopening this week, looked on with trepidation as the Americas struggled to contain the first wave of the pandemic and Asian nations like China and South Korea reported new outbreaks.
Chinese officials described the situation in Beijing as "extremely grave."
"This has truly rung an alarm bell for us," Party Secretary Cai Qi told a meeting of Beijing's Communist Party Standing Committee.
The latest Beijing outbreak started at a major whole sale food market, Xinfadi, where a "mutant strand" of coronavirus was reportedly found on a chopping block used to cut up salmon.
After a push that began June 14, the city expects to have tested 700,000 people by the end of the day, said Zhang Qiang, a Beijing party official.
About half of them were workers from the city's food markets, nearby residents and close contacts.
The party's Global Times said 1255 flights to and from the capital's two major airports were scrapped by Wednesday morning, about two-thirds of those scheduled.
Since the virus emerged in China late last year and spread worldwide, there have been more than 8.1 million confirmed cases and at least 443,000 deaths, according to a tally kept by Johns Hopkins University.
Experts say the true toll is much higher, due to the many who died without being tested and other factors.
The US has the most infections and deaths in the world, with a toll that neared 117,000 on Wednesday, surpassing the number of Americans who died in World War I.
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Arizona reported a daily high of nearly 2400 new infections for a total of more than 39,000, while in Texas, Gov. Greg Abbott insisted the state's health care system could handle the fast-rising number of new cases and hospitalisations.
Tuesday marked the eighth time in nine days that Texas set a new high for COVID-19 hospitalisation at 2,518. State health officials reported 2,622 new cases.
"It does raise concerns, but there is no reason right now to be alarmed," Abbott said.
Texas began aggressively reopening its economy May 1. Abbott noted that Texans may have become lax in wearing masks or practising social distancing and urged people to stay home as much as possible.
Canada and the US extended to July 21 a deal to keep their border closed to non-essential travel, with many Canadians fearing cases arriving from the US
As the US struggles with the first wave of the virus, other countries where it was widely thought to be under control faced disturbing developments. In South Korea, authorities reported 43 new cases amid increased public activity.
Authorities said 25 of them came from around Seoul, where hundreds of infections have been linked to nightclubs, church gatherings, e-commerce workers and door-to-door salespeople. Twelve of the new cases came from international arrivals.
China also limited other travel around the capital, keying in on hot spots.
Beijing had essentially eradicated local transmissions until recent days, with 137 new cases since last week.
On Wednesday, the city of 20 million raised its threat level from 3 to 2, cancelling classes, suspending reopenings and strengthening requirements for social distancing.
China had relaxed many lockdown controls after the Communist Party declared victory over the virus in March.
India, with the fourth-highest caseload after the US, Brazil and Russia, added more than 2000 deaths to its tally after Delhi and Maharashtra states included 1,672 previously unreported fatalities.
Its death toll of 11,903 is now eighth- highest in the world. India has reported 10,000 new infections and more than 300 deaths each day for the last two weeks.