New York City nurses on strike resumed negotiations with hospital administrators Thursday, the fourth day of what the union called the city’s biggest walkout in decades.

The New York State Nurses Association said its bargaining members began meeting with their counterparts at NewYork-Presbyterian late Thursday. The union said the nurses also planned to sit down with officials at other affected hospitals, including those operated by Mount Sinai and Montefiore, on Friday, though it said some facilities had not yet agreed to resume talks.

Each medical center negotiates with the union independently, and not every hospital run by the three health care systems is affected by the strike. The opposing sides have not met since Sunday, the day before about 15,000 unionized nurses walked off the job, the Associated Press reported.

Hospitals have hired thousands of temporary nurses to keep emergency rooms and other facilities running. The nurses say they are seeking to protect their health care benefits, while also securing contract provisions addressing staffing levels and safety against workplace violence.

At a union rally Thursday in front of Mount Sinai’s Morningside campus, Sheryl Ostroff, a Mount Sinai nurse, said nurses often bear the brunt of patients’ frustrations and that interactions can quickly become violent. She said, “I’ve been scratched in the face. I have been bitten in multiple places. I have been kicked in the ribs where it leaves bruises, spit on, pushed, punched, sexually assaulted — you name it,” and added, “It’s not acceptable, and we want our hospitals to protect us. Why is that a hard ask?”

Hospitals have said the union is seeking “unrealistic” and unaffordable pay raises. Mount Sinai said the union’s proposals would raise the average annual salary of its nurses from roughly $162,000 to nearly $250,000 in three years, while Montefiore said its proposal would raise salaries to $220,000. The union dismissed those claims as “outlandish math” and declined to provide countering figures.

In a statement Thursday, NewYork-Presbyterian said it was committed to keep negotiating for a fair and reasonable contract that reflects its “deep respect” for nurses and the critical role they play, and that recognizes the challenging realities of today’s healthcare environment.

The union said Mount Sinai’s Morningside hospital, located near Columbia University in upper Manhattan, had not yet agreed to resume contract talks. Simone Way, a nurse at Mount Sinai Morningside, said she and other nurses “have sounded the alarm for years” about proper staffing levels, and that administrators have refused to listen. Way said at the rally, “It is incredibly hard to deliver the level of care our patients deserve,” and added, “There are limits to what good nurses can do.”

A Mount Sinai spokesperson did not immediately respond to an email seeking comment on the rally or the status of contract talks. Brendan Carr, the health system’s CEO, said in a video released earlier Thursday that unionized nurses who opted to work instead of joining the picket line have been subjected to harassment and intimidation. Carr said, “Bullying, intimidating and threatening devalues nurses, undermines our culture, and is not consistent with our values at Mount Sinai,” and told hospital staff, “You deserve better.” The union dismissed those accusations as “baseless.”

Separately, the union confirmed that its member nurses on Long Island ratified new contracts Thursday with Northwell Health, the state’s largest health system. The union said the deals were reached last week and averted strikes at three Long Island hospitals, and called for roughly 5% raises in each year of the three-year pact.