New York Governor Andrew Cuomo has announced a one-mile (1.6km) coronavirus “containment zone” around a town north of New York City.
New Rochelle has seen “probably the largest cluster” of US cases, he said.
National Guard troops will be used to clean schools in the town and deliver food to any quarantined individuals.
The death toll in Italy, one of the countries worst hit by the virus, rose to 631 as the authorities placed the whole country in lockdown.
The latest increase in deaths in Italy – 168 – is the biggest the country has recorded in a single day, and the total number of cases went from 9,172 to 10,149.
What does containment mean?
New York state has 173 active cases, the most in the US, and 108 of them are in Westchester County, where New Rochelle is located.
New York City, 25 miles (40km) south of New Rochelle, has 36 confirmed cases of the virus in its population of eight million people.
Mr Cuomo said there would be no travel restrictions in New Rochelle (population 77,000) but large meeting points in the area would be closed.
Schools, gathering places and businesses in the virus hot spot will be closed for two weeks.
Officials will also set up a coronavirus testing facility at a local hospital.
“It is a dramatic action but it is the largest cluster in the country and this is literally a matter of life and death,” Mr Cuomo said, adding that numbers of cases were “going up unabated” in New Rochelle.
“You’re not containing people. You’re containing facilities.”
A synagogue is at the centre of the New Rochelle outbreak, local media report.
A man in his 50s who attended religious services is believed to be “patient zero” in the region. Around 1,000 people associated with the temple are now under quarantine.
原文出處 BBC