Thousands of nurses at three major hospitals in New York City began to strike on Monday, amid a severe flu season and broader pressures on the US healthcare system.

“All parties must return immediately to the negotiating table,” Mamdani said in brief remarks. “They must bargain in good faith.”

A labour dispute is at the centre of the conflict, with workers represented by the New York State Nurses Association arguing that hospital management is threatening to cull benefits, the union said in a statement.

Hospital management at all three systems said the decision to walk out is “reckless”, in a statement before the strike.

On Monday, Mount Sinai Health System said it has readied 1,400 qualified and specialised nurses and is “prepared to continue to provide safe patient care for as long as this strike lasts”.