In an extraordinary escalation of steps taken to mitigate the spread of coronavirus from New York, the White House announced that all visitors who recently left the city are to self-quarantine for two weeks.

The announcement came during Tuesday's coronavirus media briefing from the White House.

Coronavirus task force coordinator Dr. Deborah Birx said that about 60% of the new coronavirus cases in the U.S. were originating from the metro New York City area.

"No matter where they have gone, whether it's Florida, North Carolina, or out to the far reaches of Long Island, we are starting to see new cases across Long Island that suggests people have left the city," Birx told reporters.

"So this will be very critical that those individuals do self-quarantine in their homes over these next 14 days to make sure they don't pass the virus to others, based on the time that they left New York," she explained. "So if they're already four days out, it's just 10 more days."

Birx also told reporters that 31% of deaths from coronavirus were coming from the New York City metro region.

A graph comparing death statistics from coronavirus by the Financial Times showed the alarming rise in cases from New York:

Here's our newest chart, tracking death tolls in cities & regions:

• Madrid recorded 272 deaths today. Higher than any day in Wuhan

• New York death toll surging

• Added London and Paris. London is where Lombardia was at same stage



All charts here: https://t.co/VcSZISFxzF pic.twitter.com/M5nMI4rY69

— John Burn-Murdoch (@jburnmurdoch) March 24, 2020

A New York Times analysis found that New York City had nearly 25 times as many cases as Los Angeles, leading many to cite the greater density of the city as the cause for the disparity.



Here's the entire coronavirus briefing: