Health officials and leaders warned the world was entering a critical period that would determine just how deeply the coronavirus pandemic slices through their nations.
Chinese authorities said they would finally end a two-month lockdown in hard-hit Hubei province, where the coronavirus outbreak first began.
But nations in Europe, North America and elsewhere pressed harder to enforce the stay-at-home restrictions placed on 1.5 billion people worldwide.
Those measures could have a significant impact on the trajectory that the virus will take as it spreads across the world.
Dr Margaret Harris said overnight reporting showed 85% of the new cases are being reported in Europe and the United States.
On Monday, WHO counted more than 334,000 total cases globally.
Dr Harris said “but in fact the outbreak is accelerating very rapidly and the case numbers we received overnight will put that up considerably”.
“We are not helpless bystanders,” said WHO chief Tedros Adhanom Ghebreyesus, noting that it took 67 days to reach 100,000 cases worldwide but just four days to go from 200,000 to 300,000.
“We can change the trajectory of this pandemic.”
One viral social media video showed Italian mayors, sometimes profanely, berating their fellow citizens for not staying inside.
On Capitol Hill, a nearly two trillion dollar plan that would prop up businesses and send money to American households has stalled in Washington for days, but officials said they expect to reach a deal later Tuesday.
It appears that it will be soon that the US, which has more than 46,000 infections and 530 deaths, overtakes hard-hit Italy in the number of infections.
Authorities say the US is on track to eventually overtake China’s nearly 82,000 infections and how soon that happens depends on how seriously Americans take the state-at-home restrictions.
In New York, now one of the world’s biggest virus hotspots, authorities rushed to set up the thousands of hospital beds they will need in just weeks to protect the city’s 8.4 million people.
More than 12,000 people have tested positive in the city and 125 have died. A state-wide lockdown took effect Monday.
“This is going to get much worse before it gets better,” New York governor Andrew Cuomo said.
Nearly 384,000 people worldwide have been infected and more than 16,500 have died from the virus, according to Johns Hopkins University.
In Italy, Spain and France, the pandemic is pushing national health systems to their breaking points.
The outbreak has killed more than 6,000 Italians, the highest death toll of any country.
Officials said Monday the virus had claimed just over 600 more lives, down from 793 two days earlier, offering some glimmer of hope.
The risks remain for doctors, nurses and others on the frontlines: Italy has seen at least 18 doctors with the coronavirus die.
Health authorities say Spain has registered a daily record increase in its daily virus infections and deaths.
Spain announced 6,584 new coronavirus infections on Tuesday, taking the overall total to 39, 673. The number of deaths also jumped by a record number of 514 to 2,696.
“This is the tough week,” said Fernando Simon, the head of the Spanish health emergency co-ordination centre, at a daily briefing.
Mr Simon also said some 5, 400 health workers were infected.
A Madrid ice rink is now being used as a makeshift morgue as the number of bodies of virus victims in the Spanish capital mounts.
Overwhelmed by a virus hotspot in its eastern city of Mulhouse, France was getting help from hospitals in neighbouring Germany and Switzerland.
Asian stock markets reacted positively Tuesday, markets in Japan and South Korea posting significant gains after the Federal Reserve said it will lend to small and large businesses and local governments to help them through the crisis.
China barred people from leaving or entering the city on January 23, and soon expanded that to cover most of Hubei province, home to 70 million people.
On Tuesday, after more than a week in which China said the vast majority of new virus cases were imported from abroad, authorities said the restrictions in Hubei would end.
People cleared by health authorities would be able to leave the province after midnight. Wuhan itself will remain locked down until April 8.
For most people, the coronavirus causes only mild or moderate symptoms, such as fever or coughing.
In contrast to other European nations, German health authorities offered some hope that the country has flattened the exponential spread of the virus, which has already infected nearly 30,000.
Chancellor Angela Merkel’s government approved a massive new aid package to cushion the economic fallout of the outbreak.
On the sports front, Japan’s prime minister and the head of the International Olympic Committee were to hold talks Tuesday as they consider postponing this summer’s games in Tokyo.