Negotiations to keep 10,000 New York City nurses from walking off the job headed into a final weekend as some major hospitals were already preparing Friday for a potential strike by sending ambulances elsewhere and transferring some patients, including vulnerable newborns.

The walkout could start early Monday at several private hospitals, including two of the city's biggest: Mount Sinai Hospital in Manhattan and Montefiore Medical Center in the Bronx, each of which has more than 1,000 beds.

They and a handful of other hospitals are bargaining with nurses who want raises and an end to what they say are untenable staffing squeezes, nearly three years into the coronavirus pandemic.

“New York City hospitals have violated our trust through years of understaffing, and that understaffing has only gotten worse since the start of the COVID-19 pandemic,” nurses' union President Nancy Hagans said at a news briefing Friday. “It’s time they come to the table and deliver the safe staffing standards that nurses and our patients deserve.”

The negotiations follow a number of job actions at other U.S. hospitals as nurses come through a period of shouldering health risks and huge workloads at the peak of the virus crisis. The industry is facing burnout that has since driven many nurses from the profession, or at least from full-time hospital jobs.

Nurses at a Massachusetts hospital went on strike for nearly 10 months ending last January, marking the longest nursing walkout in state history. Thousands of nurses at two California hospitals were on strike for a week in May.

Talks took an acrimonious turn at Mount Sinai, where the union — the New York State Nurses Association — said management had walked away from the bargaining table and called off negotiations Friday.

“Shame on you, Mount Sinai,” Hagans said.

The hospital retorted that the union was being “reckless” and holding out for higher raises at Sinai than it had just achieved in tentative contract agreements reached with some other hospitals.

“The union is jeopardizing patients’ care, and it’s forcing valued Mount Sinai nurses to choose between their dedication to patient care and their own livelihoods,” the hospital said in a statement that called for the union to “meet us back at the bargaining table.”

Hagans said the union was prioritizing patient care by insisting on more robust staffing.

Faced with a possible strike, Mount Sinai said it started canceling some elective surgeries, diverting most ambulances and transferring some patients — including newborns in intensive care — from its flagship hospital and two affiliates, Mount Sinai West and Mount Sinai Morningside. Each has about 500 beds.

If there's a strike, the Morningside campus will operate only an emergency room and inpatient child psychiatry ward, according to a message the hospitals' presidents sent to staffers Wednesday.

Negotiations also continued at Montefiore and two other hospitals, the roughly 850-bed BronxCare Health System and 300-bed Flushing Hospital Medical Center, which is in Queens.

Flushing spokesperson Michael Hinck said negotiations were progressing. Spokespeople for Montefiore and BronxCare had no immediate comment Friday.

BronxCare said Thursday it was confident about eventually reaching an agreement, while Montefiore Senior Vice President Joe Solmonese said nurses were rejecting a “generous” offer. He said it mirrored raises the union had agreed to elsewhere, while also adding 78 more emergency room nurses and making other increases in pay, benefits and staffing.

On Dec. 30 — a day before their contracts expired — the nurses gave 10 days' notice of an intended strike. Such notice is legally required so hospitals have time to line up temporary replacements.

One big medical center, NewYork-Presbyterian Hospital, reached a tentative agreement with the union the next day. Maimonides and Richmond University medical centers struck tentative deals Jan. 4. All three pacts call for a series of annual raises of 7%, 6% and 5% for about 6,000 nurses total, according to the union.

But “it’s not just about compensation,” Hagans said at a briefing Thursday. “It’s about caring for our patients. It’s about safety.”

The nurses are pressing for commitments to what they consider gold-standard staffing levels, such as having at least one nurse for each of the sickest patients in intensive care, and one nurse to about four patients in a typical medical-surgical unit.

Meanwhile, negotiations also are ongoing with four Brooklyn private hospitals. Nurses there have yet to authorize a strike, though votes are in progress, Hagans said.