NEW YORK — Hospitals throughout New York City reported a steady rise in the number of patients requiring intensive care Monday as confirmed coronavirus cases continued to swell, and state and local leaders renewed calls for more beds and lifesaving medical supplies.

As of Monday afternoon, Northwell Health, a network of 19 hospitals in the region, had more than 700 patients with covid-19, the highly contagious disease caused by the novel coronavirus, said spokesman Terry Lynam.

“In anticipation of the surge, we discharged last week several thousand patients, and on top of that, effective a week ago today, we canceled elective surgeries,” he said, noting that the move reduced inpatient volume by about 30 percent. “Right now, we have ample capacity in our hospitals, [but] patients that require intensive care, that is increasing dramatically.”

Northwell has doubled its stock of ventilators, considered necessary to treat covid-19 patients in respiratory distress, Lyman said, spending millions on the machines that cost between $10,000 and $40,000. The network employs about 72,000 people, but more manpower is needed, he said, to staff facilities in anticipation of a patient surge that threatens to overwhelm hospitals’ ability to care for those who become gravely ill. The private health-care network is looking outside the area for medical professionals and seeking nurses to work on a per diem basis.

New York continues to lead the country in confirmed covid-19 cases, and the numbers are expected to accelerate rapidly in the coming days and weeks. Statewide, there were about 20,000 confirmed cases Monday, about 5,000 of which were new. New York City had more than 13,000 cases, with more than 2,200 hospitalized and 525 in intensive care, according to the most recently available data. And while officials attributed the spike in part to expanded testing, fear remains that hospitals are neither prepared nor equipped for what’s to come.

For now, in the second week of a widespread quarantine that’s been ordered throughout the state, hospitals in New York City continued to fare relatively well, according to two doctors who work at separate facilities and, like others, spoke on the condition of anonymity because they were not authorized to speak to the media. Theirs were still functioning smoothly, they said, although doctors and other health-care workers were feeling strain and stress about the shortage of proper masks and protective gear.

Their emergency rooms remain open and, with most elective surgeries postponed or canceled, the hospitals overall had become quieter and emptier than usual.

Both said intensive care units were beginning to fill up with patients on ventilators but had not reached a crisis yet. Some hospitals have plans to expand intensive care to other floors, though that move will be limited by factors such as the number of rooms where patients can be isolated and the number of ventilators.

Approximately 280 people were hospitalized with covid-19 at NYU Langone Health facilities across New York City and Long Island, according to a person familiar with the matter who said that officials there have focused on expanding the number of intensive care beds, reducing overcrowding and rationing protective equipment such as masks, gloves and gowns.

“We have a sufficient supply of ventilators at this time,” this person said. “We also have about 10 days of PPE [personal protective equipment]. We are rationing them through re-use and sterilization.”

The shortage of N95 masks, considered necessary by health-care professionals because they screen out most small particles, remains a particular concern in New York and elsewhere across the country. Judy Sheridan-Gonzalez, a practicing nurse and president of the New York State Nurses Association, described the organization’s 40,000 members as “terrified” and faulted the Trump administration for its haphazard initial response to threat.

“We don’t feel prepared at all,” she said. “We’re not given the supplies that we believe we need.”

Gov. Andrew M. Cuomo (D) said over the weekend that 1 million N95 masks were being rushed to New York City. He also has focused on hospital capacity and on Monday ordered medical facilities statewide to expand their number of beds by 50 percent.

In the afternoon, Cuomo toured the Javits Center, a massive convention hall that hosts Comic-Con and major auto shows that was being converted to a 1,000-bed temporary hospital with the aid of the Army Corps of Engineers.

New York Mayor Bill de Blasio (D) said hospital beds were being erected on a rolling basis around the city. At the Coler Rehabilitation and Nursing Care Center on Roosevelt Island, 100 new beds were going to be available this week with an additional 240 expected next week.

New York City’s 11 public hospitals have enough equipment and supplies to get through this week, he told CNN early Monday. The city was in desperate need of ventilators, especially, and appealed to private citizens to provide them if possible. “If we don’t get ventilators this week, we’re going to start losing lives we could have saved,” de Blasio said. “I can’t be blunter than that.”

Following a conversation with President Trump and Vice President Pence, the city was set to receive 400 ventilators from the federal stockpile, he said later.

The story of preparedness in New York to date has been one of piecemeal efforts to accumulate resources. “Our need for ventilators is in the thousands, but we’re going to fight every day to stay ahead of this curve,” de Blasio said. “Four hundred ventilators is a huge step forward to help us get through this week and into the next.”

Bernstein reported from Washington. Brittany Shammas in Washington contributed to this report.