Just hours after the president went on Fox News implying that New York doesn't really need the 30,000 ventilators New York Gov. Andrew Cuomo requested, New York City's mayor also took to the airwaves to insist that his city is, in fact, in dire need of them.

"Here's the reality in New York City," Mayor Bill de Blasio told George Stephanopoulos on "Good Morning America." "People are answering the call – healthcare workers, first responders – but we have to be real honest about where this is going. I can tell you, right now, we have enough supplies to get through this week and next week in our hospitals. That's all I can guarantee you. And after that, unfortunately, we think this crisis is going to grow, through April into May. That's the truth."

The mayor also spoke directly to President Trump's insinuation that tens of thousands of ventilators "are just bigger" than cities like New York are going to need.

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"When the president says the state of New York doesn't need 30,000 ventilators," De Blasio said. "With all due respect to him, he's not looking at the facts of this astronomical growth of this crisis… We believe over half the people in this city will ultimately be infected. Over half."

That projection may sound astronomical, but it's actually in line with what experts have been saying with regards to the impact of COVID-19 on the global population.

On March 2, CBS News' Jim Axelrod spoke to one of the country's top experts on viruses, Marc Lipsitch from Harvard University, who cautioned that 40-70% of the world's population could become infected with coronavirus — and from that number, 1% of people who get symptoms could die.

On Friday morning, Mayor De Blasio insisted that for 20% of New York City's coronavirus patients, the battle with the disease would prove "tough." He reiterated that the presence of adequate ventilators in the city's hospitals would mean the difference between life and death.

"Thank God for 80% that will be very little impact in truth," he said. "For about 80%, we see this consistently, it's like having a cold or flu-type dynamic and you get through it in seven to ten days… but for 20% of the people infected, it's going to be tough. And for some of them, of course, it's going to be fatal. So, when you look at these overall numbers, we've got to be honest about how it grows before it comes- you know, before it comes down, we're going to go through a really sharp growth period."

When asked about Mr. Trump's hope that the U,S, economy could reopen by Easter and whether we should expect for New York City to be closed through May, the mayor said yes, "we have to be ready for that."