WASHINGTON/NEW YORK (REUTERS, AFP) - The United States government raced on Tuesday (March 31) to build hundreds of makeshift hospitals near major cities to ease the strain on overwhelmed healthcare systems as President Donald Trump predicted a “very painful” two weeks ahead.

The number of deaths in the US from coronavirus has surpassed that reported by China, where the pandemic began in December, according to a toll published on Tuesday by Johns Hopkins University.

There have been 3,415 deaths in the US from the virus, the Baltimore-based university said, more than the 3,309 reported officially in China.

Italy has suffered the most virus deaths – 12,428 – according to Johns Hopkins, followed by Spain with 8,269 and then the US.

The death toll in the US, tallied by Reuters, stood at 800 for Tuesday, the most for a single day so far.

Nearly half those deaths were in New York state, still the epicentre of the coronavirus pandemic, and New York City Mayor Bill de Blasio pleaded for reinforcements from the Trump administration, saying the worst may still be weeks away.

"This is the point at which we must be prepared for next week, when we expect a huge increase in the number of cases. What I asked very clearly, last week, was for military medical personnel to be deployed here," Mr de Blasio said at the Billie Jean King National Tennis Centre in Queens, where a field hospital was being built.

Mr de Blasio, a Democrat, said he had asked the White House for an additional 1,000 nurses, 300 respiratory therapists and 150 doctors by April 5 but had yet to receive an answer from the Trump administration.

All told, more than 3,700 people have died from Covid-19 in the US during the outbreak, more than the number who died in the Sept 11, 2001, attacks. The total confirmed US cases rose to 184,000, up 21,000 from the day before.

White House medical experts have said between 100,000 to 200,000 people could ultimately die from the respiratory disease in the US this year, despite orders in most major cities confining Americans to their homes except for the most necessary outings.

More than 30 states have ordered people to stay at home to contain the virus, a move that has strangled the economy and left millions without a pay cheque, at least temporarily.

The US Army Corps of Engineers was searching for hotels, dormitories, convention centres and large open spaces to build as many as 341 temporary hospitals, Lieutenant-General Todd Semonite, the head of the corps, told the ABC News Good Morning America programme.

The corps, the engineering arm of the US Army, has already joined with New York state officials to convert New York City's Jacob Javits Convention Centre into a 1,000-bed hospital in the space of a week.

DOCTORS EXHAUSTED

In Los Angeles, the city's massive convention centre was being converted to a federal medical station by the National Guard, Mayor Gil Garcetti said on Twitter.

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In California, the most populous US state, the number of patients with the illness surged over the past few days, with more than 7,400 cases confirmed as of Tuesday and more than 150 deaths.

The pandemic has taken a toll on doctors, nurses and other healthcare workers, who are overworked and lack the medical devices and protective gear needed.

"The duration itself is debilitating and exhausting and depressing," New York Governor Andrew Cuomo told a news conference where he revealed that his brother, CNN news anchor Chris Cuomo, had tested positive for the virus.

"I'm speaking to healthcare professionals who say, 'Look, more than physically tired, I'm just emotionally tired'."

US coronavirus-related deaths still trail those of Italy and Spain with more than 11,000 and 8,000 reported fatalities, respectively.

China has reported 3,305.

Worldwide, there are now more than 800,000 cases of the highly contagious illness caused by the virus and more than 40,000 deaths reported.

An intensive care nurse at a major hospital in Manhattan said he had been shocked by the deteriorating conditions of young patients with little or no underlying health issues.

"A 28-year-old, healthy fellow ICU nurse is currently so sick that he has difficulty walking up a single flight of stairs without gasping for breath," said the nurse, requesting anonymity because he was not authorised to speak to the media.

The medical surgery unit at New York-Presbyterian Hospital's Hudson Valley branch has 17 coronavirus patients, more than half its capacity, said nurse Emily Muzyka, 25.

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"I had a meltdown and cried to my boyfriend," Ms Muzyka said after a relatively healthy, 44-year-old patient declined quickly and required ventilation.

No-visitor policies mean very ill patients may die alone.

"I've held patients' hands through their final breaths in the past," Ms Muzyka said.

"It's a lonely death."

Congress debated whether to consider another economic relief Bill after passing a landmark US$2.2 trillion (S$3.1 trillion) package last week that will send cheques to taxpayers, inject cash into businesses and fund hospitals.

House of Representatives Speaker Nancy Pelosi said Congress should focus next on state and local recovery efforts, but Senate Majority Leader Mitch McConnell urged a "wait-and-see" approach.

Goldman Sachs on Tuesday revised down its already pessimistic outlook for the US economy, forecasting it would shrink 34 per cent in the second quarter and projecting unemployment would rise to 15 per cent.