New York Gov. Andrew Cuomo and New York Mayor Bill DeBlasio speak during a news conference on the first confirmed case of COVID-19 in New York, on March 2, 2020 in New York City.

New York Gov. Andrew Cuomo warned Monday that the COVID-19 outbreak will stretch U.S. hospitals to their maximum capacity, saying the nation doesn't have enough hospital beds to handle a pandemic.

"When we're going to have a real problem is when cases hit their apex and descend on the health-care system and we will not have enough hospital beds," Cuomo said Monday during a press call on the COVID-19 pandemic.

Cuomo said he sent a letter to President Donald Trump asking him to deploy the Army Corps of Engineers to the state to "start building temporary health-care capacity." He also criticized the federal government's response to the pandemic, saying it has "been behind from day one on this crisis."

"States, frankly, don't have the capacity or the power to make up for the federal government," Cuomo said. He called on U.S. officials to coordinate closings across the country, saying state and local leaders have adopted a "hodgepodge" of different actions.

The threat of COVID-19 comes at an already busy time for most U.S. hospitals. Another serious respiratory illness, the seasonal flu, is at its peak in the United States, with more than 36 million cases and many hospitals stretched thin. Earlier in the outbreak, doctors warned that a larger outbreak of the new coronavirus across the U.S. could overwhelm emergency rooms and quickly cause supply shortages of some crucial medical supplies.

The governors of New York, New Jersey and Connecticut announced Monday they have agreed to a common set of rules to reduce density throughout the region, closing movie theaters, most restaurants and bars and limiting public gatherings to fewer than 50 people.

The announcement came after the Centers for Disease Control and Prevention on Sunday urged people across the U.S. to cancel or postpone events with 50 or more attendees for the next eight weeks to try to contain the fast-moving coronavirus pandemic.

The number of cases in New York state has reached at least 729 people as of Sunday afternoon, according to the state health department.

Cuomo said Friday that New York was ramping up its testing, having just received federal approval to allow 28 labs across the state that can process complex tests to begin running coronavirus tests. He said at the time the state should be able to process 6,000 tests a day. So far, the state has been able to run a total of just 3,000 tests so far, he said Friday.