New York City accounts for roughly a third of all the coronavirus cases in the nation with 5,151 confirmed infections as of Friday morning, Mayor Bill de Blasio said.

"We are now the epicenter of this crisis," he said at a press conference, adding that 29 residents have died. Some 52 New York City police officers are among those infected, city officials said.

The mayor said he's been warning people that the city will run out of protective gear for medical workers in two or three weeks if cases keep rising at this rate.

"If you feel afraid, you are not alone, if you're anxious you are not alone," de Blasio said. "New Yorkers are so strong. There are other places in this country this might be a particularly shock to the system, but here ... we are tough people by nature."

De Blasio urged residents to go outside only if they need to and to remain 6 feet away from other people if they do go out. He said the city won't approve permits for events or sports in parks, although people are still allowed to use them.