New York authorities 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, Detroit and Southern California, the nation’s biggest city was the hardest hit of them all, accounting for most of the state’s dead, with bodies loaded onto refrigerated morgue trucks by gurney and forklift outside overwhelmed hospitals, in full view of passing motorists.

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.”

Across the U.S., Americans braced for what President Donald Trump warned on Tuesday could be “one of the roughest two or three weeks we’ve ever had in our country.” The White House projected 100,000 to 240,000 deaths in the U.S. before the crisis is over, and Vice President Mike Pence said models for the outbreak show the country on a trajectory akin to hard-hit Italy’s.

Under growing pressure, Florida Gov. Ron DeSantis belatedly joined Cuomo and governors in more than 30 states in issuing a statewide stay-home order, taking action after conferring with fellow Republican Trump. The governors of Pennsylvania and Nevada, both Democrats, took similar steps. Mississippi’s GOP was expected to follow suit.

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 200,000 infections and about 4,400 deaths, with New York City accounting for about 1 out of 4 dead.

In New York, more than 80,000 people have volunteered as medical reinforcements, including recent retirees, health care professionals taking a break from their regular jobs and people between gigs.

Few have made it into the field yet, as authorities vet them and figure out how to use them, but hospitals are expected to begin bringing them in later this week.

Those who have hit the ground already, many brought in by staffing agencies, have discovered a hospital system being driven to the breaking point.

“It’s hard when you lose patients. It’s hard when you have to tell the family members: ‘I’m sorry, but we did everything that we could,’” said nurse Katherine Ramos, of Cape Coral, Florida, who has been working at New York Presbyterian Hospital. “It’s even harder when we really don’t have the time to mourn, the time to talk about this.”

To ease the crushing caseload, the city’s paramedics have been told they shouldn’t take fatal heart attack victims to hospitals to have them pronounced dead. Patients have been transferred to the Albany area. A Navy hospital ship has docked in New York, the mammoth Javits Convention Center has been turned into a hospital, and the tennis center that hosts the U.S. Open is being converted to one, too.

With New York on near-lockdown, the normally bustling streets in the city of 8.6 million are empty, and a siren to some is no longer just urban background noise. Cuomo moved to close the city’s playgrounds because of too much crowding, but people can still use wide-open green spaces as long as they stay 6 feet apart. Police went around in patrol cars, blaring warnings to obey the rules.

“After 9/11, I remember we actually wanted to hear the sound of ambulances on our quiet streets because that meant there were survivors, but we didn’t hear those sounds, and it was heartbreaking. Today, I hear an ambulance on my strangely quiet street and my heart breaks, too,” said 61-year-old Meg Gifford, a former Wall Streeter who lives on Manhattan’s Upper East Side.

Near severely swamped Elmhurst Hospital in Queens, resident Emma Sorza, 33, described an eerie scene.

“I think everyone’s just doing what they can, but at the same time it bothers you. Especially if you’re around Elmhurst, because you can hear all the ambulances, she said. “There is a truck and people are actually dying. It’s like a battlefield behind your home.”

Cuomo said projections suggest the crisis in New York will peak at the end of April, with a high death rate continuing through July.

“Let’s cooperate to address that in New York because it’s going to be in your town tomorrow,” he warned. “If we learn how to do it right here — or learn how to do it the best we can, because there is no right, it’s only the best we can — then we can work cooperatively all across this country.”

Elsewhere around the country, Florida’s DeSantis was locked in a standoff over whether two cruise ships with sick and dead passengers may dock in his state. More than 300 U.S. citizens were on board. Two deaths were blamed on the virus, and nine people tested positive, Holland America cruise line said.

DeSantis, who is close to Trump, said the state’s health system is stretched too thin to accommodate the passengers. But the president said he would speak with him. “They’re dying on the ship,” Trump said. “I’m going to do what’s right. Not only for us, but for humanity.”

In Southern California, officials reported that at least 51 residents and six staff members at a nursing home east of Los Angeles have been infected and two have died.

Even as the virus has slowed its growth in overwhelmed Italy and in China, where it first emerged, hospitals on the Continent are buckling under the load.

“It feels like we are in a Third World country. We don’t have enough masks, enough protective equipment, and by the end of the week we might be in need of more medication too,” said Paris emergency worker Christophe Prudhomme.

Spain hit a record of 864 deaths in one day, for a total of more than 9,000, while France reported an unprecedented 509 deaths and more than 4,000 in all. In Italy, with over 13,000 dead, the most of any country, morgues overflowed with bodies, caskets piled up in churches, and doctors were forced to decide which desperately ill patients would get breathing machines.

England’s Wimbledon tennis tournament was canceled for the first time since World War II.

India’s highest court ordered news media and social media sites to carry the government’s “official version” of developments, echoing actions taken in other countries to curb independent reporting.

The strain facing some of the world’s best health care systems has been aggravated by hospital budget cuts over the past decade in Italy, Spain, France and Britain. They have called in medical students, retired doctors and even laid-off flight attendants with first aid training.

The staffing shortage has been exacerbated by the high numbers of infected personnel. In Italy alone, nearly 10,000 medical workers have been infected and more than 60 doctors have died.

For most people, the coronavirus causes mild or moderate symptoms, such as fever and cough. But for others, especially older adults and people with health problems, it can cause severe symptoms like pneumonia and lead to death.

China, where the outbreak began late last year, on Wednesday reported just 36 new COVID-19 cases.

(AP)