Health Public Information Officer, Shane Reichardt organizes medical equipment inside a temporary hospital, which has been settled up by members of the California National Guard in Indio, California on Sunday. The new field hospital with 125 beds will help ease the burden on the local hospital system amid the growing COVID-19 crisis. Photo: AFP

US President Donald Trump has extended emergency coronavirus restrictions for the country where his top scientist warned up to 200,000 people could die, as Africa's biggest city prepared to go into lockdown on Monday.

The reassessment by Trump, who had previously said he wanted the country back to work in mid-April, came as Britain and hard-hit Italy warned measures to prevent the spread of the disease would be in place for months to come.

COVID-19 has already killed almost 35,000 people worldwide, according to a tally kept by Johns Hopkins University, with the number of confirmed cases nearing three-quarters of a million.

As of Sunday, more than 3.38 billion people were asked or ordered to follow confinement measures, according to an AFP database, as the virus infects every sphere of life - wiping out millions of jobs, postponing elections and clearing the sporting calendar.

Trump warned that the US crisis, which has seen a doubling of infections in only two days, would continue to get worse for some time.

"The modelling estimates that a peak in death rates are likely to hit in two weeks," he said, announcing an extension of social distancing guidelines until April 30.

"Nothing would be worse than declaring victory before the victory is won."

The president was speaking after Anthony Fauci, who leads research into infectious diseases at the National Institutes of Health, said he believed 100,000 to 200,000 Americans could die from the disease, and potentially infect millions.

Officials continued to sound the alarm over medical shortages, with some bemoaning a system that has states competing for desperately needed supplies.

"We're bidding against one another," said Michigan's Governor Gretchen Whitmer.

The human consequences of a shutdown that has seen huge chunks of the US economy grind to a halt were playing out at food banks in New York, where organizers say demand has exploded.

Trump's re-evaluation of a back-to-normal timeline came as British officials said life may not return to normal for six months.

The country's Deputy Chief Medical Officer Jenny Harries said it would be several weeks before doctors could tell if the current lockdown had slowed the spread of the disease.

In Italy, the government warned citizens should be ready for a "very long" lockdown that would only be lifted gradually, despite the economic hardship it was causing.

Yet the strains on Italian society imposed by measures that might have seemed unimaginable just weeks ago are gradually starting to show.

The starkest example came when armed police began guarding entrances to supermarkets in Sicily after reports of looting by people who could no longer afford food.

AFP