There are so many new cases of coronavirus being reported in New York City that officials are having trouble keeping up with the number, Mayor Bill de Blasio told reporters Tuesday.

"They're coming in so intensely now that being able to give you a detailed case breakdown, we're not in that position to do that at this moment because there are so many coming forward," de Blasio said, according to CNBC.

"As of 12 noon," de Blasio said at the press conference at Bellevue Hospital in Manhattan, "the number of confirmed cases in New York City is 36, that's 16 new since [Monday] and 11 new even since this morning at 7 a.m. when I last spoke about this."

Nearly 2,000 New York City residents are currently in voluntary isolation, the mayor said, adding 30 more are under mandatory quarantine.

Across the state, COVID-19 has infected more than 173 people, Gov. Andrew Cuomo said earlier in the day. Westchester County, north of New York City, has become the nation's biggest known cluster for the virus. And so, home to well over 100 cases, and Cuomo has deployed the National Guard to the area.

The move is one of the most dramatic steps taken yet to deal with the crisis in the United States. Cuomo said three schools and other gathering places will be shut down for two weeks in a containment zone in New Rochelle. Officials said the troops will help clean public spaces and deliver food to people quarantined at home in the zone, which extends a mile in all directions from a synagogue connected to some of the cases.

Officials would not say how many National Guard members would be involved, and there was no immediate sign of any troops on the streets. Apart from those who are under quarantine, residents and visitors to the community of 79,000 will be able to come and go freely, with no checkpoints set up, and businesses can remain open, officials said.

“It is a dramatic action, but it is the largest cluster of cases in the country,” Cuomo said. “The numbers are going up unabated, and we do need a special public health strategy."

New Rochelle and surrounding Westchester County account for the majority of the state's 173 coronavirus cases. New York City, with 100 times the population of New Rochelle, has 36 known infections.

New Rochelle Mayor Noam Bramson told CNN's Wolf Blitzer Tuesday that people are free to come and go, but the "containment zone" is affecting large gatherings, having a more significant impact on major institutions such as schools and houses of worship.

"It will not impact individuals, families, or businesses," he said. "This is a sensible public health measure in order to mitigate the spread of the virus in the area which has the largest concentration in our city, in our region, one of the largest concentrations in the country."

While the number of known cases is growing, Bramson noted, that is because more people are being tested, not because the virus is rapidly spreading.

Officials in New York City are still awaiting 195 test results, and 258 tests have come back negative so far. De Blasio said officials are concerned about running low on blood supplies because some companies have cancelled blood drives. He said there is no danger in giving blood.

The Associated Press contributed to this report.