New York Governor Andrew Cuomo speaks during his daily news conference amid the coronavirus outbreak on March 20, 2020 in New York City.

"Nobody can tell you is it four months, six months, eight months, nine months. But it is several months," Cuomo said. "We all have to now confront that that is a new reality. That is not going to change. You are not going to turn on the news tomorrow morning and they're going to say, 'Surprise, surprise this is all now resolved in two weeks.'"

"This could go on for several months," Cuomo said. Roughly 13% of all cases have been hospitalized, 621 of the patients have ended up in the ICU and 157 people have died, he said.

New York is the hardest-hit state in the country, ahead of New Jersey, California and Washington state, Cuomo said. New York City, alone, accounts for 12,305 confirmed infections, he said.

New York Gov. Andrew Cuomo issued an emergency order Monday directing hospitals to increase their capacity by 50% as coronavirus cases across the state surged 38% overnight to 20,875.

Cuomo estimated up to 80% of the state's more than 19.4 million residents will get the coronavirus. Last week, Cuomo estimated there are likely "tens of thousands" of COVID-19 cases in the state among residents who didn't know they had it.

"Many people will get the virus but few will truly be in danger," he said Monday.

On Sunday, Cuomo said the state had 15,168 cases, more than France or South Korea were reporting at the time and those numbers are expected to dramatically rise as the state ramps up testing.

New York and New Jersey are seeing coronavirus attack rates at least five times higher than other parts of the country, a U.S. official in charge of the White House's pandemic response efforts said Monday.

"The New York metro area of New Jersey, New York City, and parts of Long Island have an attack rate close to one in 1,000," Dr. Deborah Birx, a physician and the White House coronavirus response coordinator, said at a press briefing Monday evening. The attack rate is the percentage of a population that gets the disease.

She said roughly 28% of the specimens submitted in that region have tested positive for COVID-19, while less than 8% have tested positive for the disease in the rest of the country.

"To all of my friends and colleagues in New York, this is the group that actually needs to social distance and self-isolate," she said. "Clearly, the virus had been there for a number of weeks."

Cuomo has said he worries the outbreak will stretch U.S. hospitals to their maximum capacity, saying the nation doesn't have enough hospital beds to handle a pandemic. Hospitals across the nation are running low on personal protective equipment. Cuomo said the state has had some luck finding extra gear for doctors and nurses and is sending hundreds of thousands of surgical masks, N95 masks, gloves and gowns to hospitals across the state.

He said he would have liked for hospitals to increase their capacity by 100%, but added that would be unreasonable.

"I think it's unreasonable to tell hospitals to double their capacity," Cuomo said. "They must increase by 50% at least."

On Friday, Cuomo ordered nonessential businesses to keep 100% of their workforce at home and put in place stringent new restrictions on New Yorkers.

Cuomo said he has asked the federal government to nationalize the purchase of medical equipment and has signed off on several locations to build temporary hospitals to treat coronavirus patients.

Correction: An earlier version misstated Cuomo's ranking of states with COVID-19 cases. He said New York state has more cases than New Jersey.