New York rushed to bring in an army of medical volunteers Wednesday as the statewide death toll from the coronavirus doubled in 72 hours to more than 1,900 and the wail of ambulances in the otherwise eerily quiet streets of the city became the heartbreaking soundtrack of the crisis.

As hot spots flared around the U.S. in places like New Orleans and Southern California, the nation's biggest city was the hardest hit of them all, with bodies loaded onto refrigerated morgue trucks by gurney and forklift outside overwhelmed hospitals, in full view of passing motorists.

”It’s like a battlefield behind your home," said 33-year-old Emma Sorza, who could hear the sirens from severely swamped Elmhurst Hospital in Queens.

And the worst is yet to come.

“How does it end? And people want answers," New York Gov. Andrew Cuomo said. "I want answers. The answer is nobody knows for sure.”

President Donald Trump acknowledged that the federal stockpile is nearly depleted of personal protective equipment used by doctors and nurses and warned of trying times to come.

“Difficult days are ahead for our nation," he said. “We're going to have a couple of weeks, starting pretty much now, but especially a few days from now that are going to be horrific.”

Scientists offered more evidence Wednesday that the coronavirus can be spread by seemingly healthy people who show no clear symptoms, leading the U.S. government to issue new guidance warning that anyone exposed to the disease can be considered a potential carrier.

Stocks tumbled on Wall Street and markets around the world, a day after the White House warned Americans to brace for 100,000 to 240,000 deaths projected in the U.S. before the crisis is over. The Dow Jones Industrial Average lost more than 970 points, or over 4%.

A new report Wednesday from the United Nations said the global economy could shrink by almost 1% this year instead of growing at a projected 2.5%.

Under growing pressure, Florida Gov. Ron DeSantis belatedly joined his counterparts in more than 30 states in issuing a statewide stay-home order. The governors of Pennsylvania, Nevada and Mississippi took similar steps.

Trump said his administration has agreed to ship out 1,000 breathing machines vital for treating severe cases of COVID-19. He said the U.S. government has kept close hold on its stockpile of nearly 10,000 ventilators so they can be deployed quickly to states in need.

Meanwhile, European nations facing extraordinary demand for intensive-care beds are putting up makeshift hospitals, unsure whether they will find enough healthy medical staff to run them. London is days away from unveiling a 4,000-bed temporary hospital built in a huge convention center.

In a remarkable turnabout, rich economies where virus cases have exploded are welcoming help from less wealthy ones. Russia sent medical equipment and masks to the United States. Cuba supplied doctors to France. Turkey dispatched protective gear and disinfectant to Italy and Spain.

Worldwide, more than 900,000 people have been infected and over 45,000 have died, according to a tally kept by Johns Hopkins University, though the real figures are believed to be much higher because of testing shortages, differences in counting the dead and large numbers of mild cases that have gone unreported.

The U.S. recorded about 210,000 infections and about 4,800 deaths, with New York City accounting for about 1 out of 4 dead.