New York City Mayor Bill de Blasio announced Tuesday that a plan to open up specific streets for exercise will start in each of the five boroughs Thursday, as much of the city remains closed due to the coronavirus.

The pilot program will open up to two streets per borough and be enforced by the NYPD, the mayor said.

"Everyone wants to make sure there are spaces for folks to get their exercise, to get fresh air," de Blasio said. "But there must be enforcement."

De Blasio added that the situation will evolve and more details will be announced soon.

"Every site can and will be enforced by the NYPD and other agencies," he said."That obviously underlies our entire approach."

Earlier this week, de Blasio had said there were no plans to close city streets. Gov. Andrew Cuomo had suggested it as a way for people to spread out more outside.

"You have much less traffic in New York City because non-essential workers aren't going to work," Cuomo said Sunday. "Get creative. Open streets to reduce the density. You want to go for a walk? God bless you. You want to go for a run? God bless you. But let's open streets, let's open space - that's where people should be, in open spaces areas, not in dense locations."

As of Tuesday evening, there were 15,597 cases of coronavirus in New York City.