More than 7,000 New York City nurses are on strike, and it's unclear how long the walkout will last

More than 7,000 nurses in New York City went on strike Monday morning.

Nurses at Montefiore and Mount Sinai Hospital walked out after negotiations for a new deal were unsuccessful overnight. The New York State Nurses Association posted images of nurses on picket lines on social media Monday morning. The union gave 10-day notice of a strike on Dec. 31.

Mount Sinai has taken a host of steps in preparation for a strike, such as transferring patients, postponing surgeries, and diverting ambulances.

The nurses’ union said it had reached agreement Sunday on a tentative deal with Mount Sinai Morningside and West. Nurses still must ratify the deal.

Nurses have reached tentative agreements or new contracts with several hospitals, including BronxCare Health System, Flushing Hospital Medical Center, Maimonides Medical Center, Mount Sinai Morningside and West, NewYork-Presbyterian, Richmond University Medical Center, and The Brooklyn Hospital Center.

Nancy Hagans, a registered nurse at Maimonides Medical Center and president of the New York State Nurses Association, said there has been no discussion about a potential maximum length for a walkout.

‘We have an open ended strike .. The strike is not up to us. It’s up to the bosses,” Hagans said at a news conference Friday.

At a news conference on the picket lines Monday, Hagans said it's time for the hospitals to offer a fair contract. “Respect your nurses. Respect your patients. Respect your community," she said.

Hagans has said nurses need better staffing and higher wages. Hagans has consistently said staffing remains the key issue in the dispute, with hundreds of nursing jobs being unfilled.

New York Gov. Kathy Hochul issued a statement Sunday urging binding arbitration to resolve the dispute.

"The New York State Department of Health will continue to enforce staffing requirements under the law at these hospitals to maintain the delivery of essential health care services to the community and protect patient health and safety," Hochul said. "Likewise, the Health Department will continue to ensure that all providers are meeting the requirements of the law."

In late December, about 17,000 nurses at several New York City hospitals overwhelmingly approved a strike authorization vote. Since then, more than half of those nurses have reached at least tentative agreements.

Mount Sinai issued a statement Monday morning criticizing the nurses’ union for walking out.

“NYSNA continues its reckless behavior, rejecting Governor Hochul’s proposal for binding arbitration,” Mount Sinai said in the statement. “The Governor’s proposal would have provided a path to avoid this strike, which sadly is forcing nurses at The Mount Sinai Hospital to leave their patients’ bedsides.

“NYSNA leadership walked out of negotiations shortly after 1:00AM ET Monday morning. They refused to accept the exact same 19.1 percent increased wage offer agreed to by eight other hospitals, including two other Mount Sinai Health System campuses.”

Montefiore Medical Center issued a statement early Monday morning calling it “a sad day for New York City.”

“Despite Montefiore’s offer of a 19.1% compounded wage increase – the same offer agreed to at the wealthiest of our peer institutions - and a commitment to create over 170 new nursing positions, and despite a call from Governor Hochul for arbitration, NYSNA’s leadership has decided to walk away from the bedsides of their patients,” Montefiore said.

The New York State Nurses Association said it represents about 3,600 nurses at Mount Sinai, and about 3,500 nurses at Montefiore.

The union issued a statement urging residents to go to the hospital if they are sick, regardless of the strike. "Patients should seek hospital care immediately if they need it. We would rather be the ones providing that care, but our bosses have pushed us to be out here instead," the association said in a statement.

The association touted the support of city and state labor leaders and lawmakers in the strike.

U.S. Rep. Jamaal Bowman, a New York Democrat, joined nurses on the picket lines Monday.

"It's great to hear that most nurses have finally got their fair contract in New York City, but we still have 7,000, as we speak, without a fair contract," Bowman said on the picket lines Monday morning. "Montefiore, Mount Sinai, it's time for you to step up and get this done."