Europe was reeling from a staggering surge in coronavirus deaths on Saturday, still days or weeks from what experts desperately hope will be the epidemic's peak.

Grim new tolls from Italy and Spain came as the IMF confirmed the world economy has plunged into a historic slump, and the US invoked wartime procurement powers.

More than 600,000 cases of the new coronavirus have been officially recorded around the world since the outbreak of the epidemic, according to an AFP tally.

Variations in testing regimes mean the true number is likely far higher still, and confirmed deaths are mounting.

Spain recorded 832 fatalities in 24 hours, bringing its toll to 5,690, second in the world only to Italy, which confirmed a one-day record of 969 on Friday.

Elsewhere, Iran announced 139 more deaths and India sealed off a dozen Punjab villages that had been visited by a guru now known to be infected and a possible "super-spreader".

And in South Africa, Johannesburg police resorted to rubber bullets to enforce social distancing on a crowd queueing for supplies outside a downtown supermarket during a national lockdown.

The United States now has the world's highest single number of Covid-19 cases but per capita European nations are still the worst hit, with emergency services struggling to cope.

Wuhan partially reopens

However, two months of almost total isolation appear to have paid off in China's Wuhan — where the virus first emerged — which was partially reopened.

Since January, residents have been forbidden to leave, with roadblocks installed and millions subjected to dramatic restrictions on their daily life.

But on Saturday people were allowed to enter the city, and most of the subway network restarted. Some shopping centres will open their doors next week.

The European Union economy has already been disrupted by border closures and stay-at-home orders, and Italian Prime Minister Giuseppe Conte warned that the bloc could lose its legitimacy.

"If Europe does not rise to this unprecedented challenge, the whole European structure loses its raison d'etre to the people," he told the Il Sole 24 Ore newspaper.

Italy, backed by France and Spain, wants Europe to come up with a stronger financial response to the crisis, but Germany and the Netherlands are resisting calls to pool national debts.

Meanwhile, on Friday, IMF chief Kristalina Georgieva said massive spending will be needed to help developing nations, warning: "It is clear that we have entered a recession."

In the US, which now has more than 104,000 Covid-19 patients, President Donald Trump invoked emergency powers on Friday to force a private company to make medical equipment.

Giant US stimulus package

"Today's action will help ensure the quick production of ventilators that will save American lives," Trump said on Friday, as he issued the order to auto giant General Motors.

With 60 per cent of the country in lockdown, and infections skyrocketing, Trump also signed the largest stimulus package in US history, worth $2 trillion.

It came as Italy recorded almost 1,000 deaths from the virus on Friday — the worst one-day toll anywhere since the pandemic began.

One coronavirus sufferer, a cardiologist from Rome who has since recovered, recalled his hellish experience at a hospital in the capital.

"The treatment for the oxygen therapy is painful, looking for the radial artery is difficult. Desperate other patients were crying out, 'enough, enough'," he told AFP.

Infection rates in Italy are on a downward trend, but the head of the national health institute Silvio Brusaferro said it was not out of the woods yet, predicting "we could peak in the next few days".

Spain has the world's second-highest coronavirus death toll after Italy and the number of cases jumped to 72,248 on Saturday as the country moves to significantly increase testing.

Smaller Belgium and Luxembourg also saw a steep climb in deaths, with 353 recorded in the former on Saturday — up from 289 the day before — and 15 in the grand duchy, up from nine.

Europe has suffered the brunt of the coronavirus crisis in recent weeks, with millions across the continent on lockdown and the streets of Paris, Rome and Madrid eerily empty.

In Britain, the men leading the country's fight against the coronavirus — Prime Minister Boris Johnson and his Health Secretary Matt Hancock — have both tested positive for Covid-19.

Meanwhile, other countries across the world were bracing for the virus's full impact, with AFP tallies showing more than 26,000 deaths globally.

The World Health Organisation's regional director for Africa warned the continent faced a "dramatic evolution" of the pandemic, as South Africa also began life under lockdown and reported its first virus death.

Younger patients

In the US, known infections jumped past 104,000, the world's highest figure, with 1,711 deaths, according to Johns Hopkins University.

In New York City, the US epicentre of the crisis, health workers battled a surging toll — including an increasing number of younger patients — while struggling with a severe shortage of protective equipment.

"Now it's 50-year-olds, 40-year-olds, 30-year-olds," said one respiratory therapist.

To ease the strain on virus-swamped emergency rooms in Los Angeles, a giant US naval hospital ship docked there to take patients with other conditions.

In New Orleans, famed for its jazz and nightlife, health experts believe the month-long Mardi Gras in February could be largely responsible for its severe outbreak.

"This is going to be the disaster that defines our generation," said Collin Arnold, director of the Office of Homeland Security and Emergency Preparedness for New Orleans.

But as Europe and the US struggle to contain the pandemic, aid groups have warned the death toll could be in the millions in low-income countries and war zones such as Syria and Yemen, where hygiene conditions are already dire and healthcare systems are in tatters.