The outbreak is gathering pace in Latin America. The governments of El Salvador and Guatemala announced curfews on Saturday, Colombia recorded its first confirmed death, and Ecuador's health and labor ministers resigned after cases in that country topped the 500 mark, The Guardian newspaper reported.

Salvadoran President Nayib Bukele ordered residents to quarantine at home for 30 days, a measure he admitted would cause "discomfort" but that he said was necessary to slow the spread of the disease, according to The Guardian.

Japan's foreign ministry has advised Japanese people to avoid nonessential and non-urgent travel to the US, Reuters said.

Tokyo 2020 organizers have started drafting possible alternatives to holding the Olympics this summer, said Reuters quoting two sources familiar with the talks.

But the Japanese government says postponement is not an option. And the Olympic torch relay will kick off in Fukushima prefecture on Thursday.

Some 10,000 runners are due to carry the torch through 859 municipalities across all 47 Japanese prefectures in 121 days before reaching Tokyo in July for the opening ceremony, Japan Times reported.