NEW YORK (AP) Striking nurses chanted and waved signs outside two large New York City hospitals Monday after a weekend of negotiations over pay and staffing levels did not produce a deal for a new contract.

The walkout involves as many as 3,500 nurses at Montefiore Medical Center in the Bronx and about 3,600 at Mount Sinai Hospital in Manhattan. Patients are likely to see disruptions in care such as emergency room visits and childbirth.

The New York State Nurses Association, which represents the workers, said it was being forced into the drastic step because of chronic understaffing that leaves them caring for too many patients.