He also asked the federal authorities to give New York permission to test patient samples for the coronavirus in a laboratory in the state, rather than sending them to the C.D.C. in Atlanta.

In New York City, where six people have been tested for the coronavirus and cleared, Mayor de Blasio has reiterated that officials are equipped for an outbreak. According to my colleagues, the city has made 1,200 hospital beds available for people suspected of having the coronavirus, and has distributed 1.5 million face masks to health care workers.

“This is something we can handle,” Mr. de Blasio said this month.

The Metropolitan Transportation Authority announced yesterday that it was working with state and federal health officials to develop contingency plans, but did not offer details. According to a document prepared by City Hall, public transit ridership could be limited or staggered to help prevent the spread of the disease.

Patrick J. Foye, the M.T.A. chairman, also said the authority had increased its supply of masks and other materials.

Thousands of signs on subways and buses encourage riders to wash their hands and avoid close contact with sick people.

The context

The new strain of coronavirus was first identified in China, and the number of confirmed cases globally has reached more than 82,000. Almost 3,000 people have died. The vast majority of the cases are in China; the rest of the globe accounts for fewer than 4,000 of the infections and just more than 50 of the deaths.

There are at least 60 confirmed cases in the United States. In New York, state officials have asked some 700 individuals who have recently visited China to voluntarily quarantine themselves.