Thousands of nurses went on strike Monday at two of New York City's major hospitals after contract negotiations stalled over staffing and salaries nearly three years into the coronavirus pandemic.

The privately owned hospitals were postponing nonemergency surgeries, diverting ambulances to other medical centers, pulling in temporary staffers, and assigning administrators with nursing backgrounds to work in wards in order to cope with the walkout.

As many as 3,500 nurses at Montefiore Medical Center in the Bronx and about 3,600 at Mount Sinai Hospital in Manhattan were off the job. Hundreds picketed, some singing the chorus from Twisted Sister’s 1984 hit “We’re Not Gonna Take It,” outside Mount Sinai. It was one of many New York hospitals deluged with COVID-19 patients as the virus made the city an epicenter of deaths in spring 2020.

“We were heroes only two years ago,” said Warren Urquhart, a nurse in transplant and oncology units. “We was on the front lines of the city when everything came to a stop. And now we need to come to a stop so they can understand how much we mean to this hospital and to the patients.”

The union for nurses, the New York State Nurses Association, said they had to strike because chronic understaffing leaves them caring for too many patients.

Jed Basubas said he generally attends to eight to 10 patients at a time, twice the ideal number in the units where he works. Nurse practitioner Juliet Escalon said she sometimes skips bathroom breaks to attend to patients. So does Ashleigh Woodside, who said her 12-hour operating-room shifts often stretch to 14 hours because short staffing forces her and others to work overtime.

“We love our job. We want to take care of our patients. But we just want to d it safely and in a humane way, where we feel appreciated,” said Woodside, who has been a nurse for eight years.

The hospitals said they had offered the same raises — totaling 19% over three years — that the union had accepted at several other facilities where contract talks reached tentative agreements in recent days.

Montefiore said it had agreed to add 170 more nurses. Mount Sinai’s administration said the union’s focus on nurse-to-patient ratios “ignores the progress we have made to attract and hire more new nurses, despite a global shortage of healthcare workers that is impacting hospitals across the country.”

The hospitals said Monday that they had prepared for the strike and were working to minimize the disruption.

“We remain committed to seamless and compassionate care, recognizing that the union leadership’s decision will spark fear and uncertainty across our community,” Montefiore said. “This is a sad day for New York City.”

Mount Sinai called the union “reckless.”

Gov. Kathy Hochul urged the union and the hospitals late Sunday to take their dispute to binding arbitration. Montefiore’s administration had said it was willing to let an arbitrator settle the contract “as a means to reaching an equitable outcome.”

The union did not immediately accept the proposal. In a statement, it said Hochul, a Democrat, “should listen to the frontline COVID nurse heroes and respect our federally-protected labor and collective bargaining rights.”

Both hospitals had been getting ready for a walkout by transferring patients, including intensive-care newborns at Mount Sinai.

Montefiore and Mount Sinai are the last of a group of hospitals with contracts with the union that expired simultaneously. The Nurses Association had i nitially warned that it would strike at all of them at the same time — a potential calamity even in a city with as many hospitals as New York.

But one by one, the other hospitals struck agreements with the union as the deadline approached.

Nurses at NewYork-Presbyterian Hospital ratified a deal Saturday that will give them raises of 7%, 6%, and 5% over the next three years while also increasing staffing levels. That deal, which covers 4,000 nurses, has been seen as a template for the negotiations with other hospital systems.

Nurses at two facilities in the Mount Sinai system also tentatively agreed to contracts Sunday. But there was no such pact at the system's flagship hospital on Manhattan's Upper East Side.

The New York State Department of Health provided this substance in response to the ongoing strikes:

"The New York State Department of Health continues to work closely with New York City and affected hospitals to ensure the health and safety of patients as the New York State Nurses Association (NYSNA) strikes proceed at Mount Sinai and Montefiore Hospitals. The Department has deployed surveyors to the affected hospitals to ensure adequate health care resources are maintained to meet the needs of the community; to review and enforce required minimum staffing levels; to provide guidance and collect information regarding facility readiness to maintain operations; and to coordinate with partners, including the New York City Department of Health and Mental Hygiene (NYCDOHMH), New York City Emergency Management (NYCEM) and FDNY EMS. Staffing level requirements at affected facilities may be achieved by acquiring additional staff resources, reducing or postponing elective procedures, and transferring eligible patients to other hospitals within the regional hospital system, which has capacity. To file a complaint about current services at an impacted - or any - hospital, individuals may call 1-800-804-5447 or complete the Health Facility Complaint Form, so appropriate action can be taken.”