More on Brazil, which is by far the worst affected country in South America.

A study by the University of Washington has warned that the country's death toll could climb to 125,000 by early August.

That's a five-fold increase from its current recorded tally of 24,500.

“Brazil must follow the lead of Wuhan, China, as well as Italy, Spain, and New York by enforcing mandates and measures to gain control of a fast-moving epidemic," wrote Dr Christopher Murray, who worked on the study.

The stark prediction came shortly after Brazil's daily death toll surpassed that of the United States for the first time. It recorded 807 deaths on Monday, while 620 people died in the US.

Health experts in Brazil have warned that the real number of confirmed infections may be far higher than the official records, due to a lack of testing.

And far-right president Jair Bolsonaro has been strongly criticised both at home and abroad for his handling of the crisis. He has downplayed the virus as "a little flu" and said its spread is inevitable.