A 52-year-old caregiver was charged in the knife attack on five people, including three newborn babies, at a home that was apparently being used as an unlicensed nursery for new mothers and their children.
Yufen Wang, of Flushing, Queens, was arraigned on Monday on charges of attempted murder and criminal possession of a weapon, prosecutors said.
A message left with her lawyer wasn't immediately returned.
Wang is accused of stabbing and slashing a father, a female worker and three newborn babies inside the three-story residence in the Flushing section of Queens early on Friday. All were hospitalised and are expected to survive.
Wang was apprehended in the building's basement with self-inflicted wounds to her neck and wrist.
"The defendant was hired to care for and protect the infants, sadly she was the danger," Queens District Attorney Richard Brown said.
The motive for the attack is unclear.
The nursery is in a neighbourhood popular with Chinese immigrants. Nine babies were there during the attack, and the place had at least 11 cribs, the district attorney's office said.
Local elected officials said it appeared it was an unlicensed facility for new mothers and their babies to convalesce for a month, in keeping with Chinese tradition.
Wang's next court date is October 19. If convicted, she faces between five and 25 years in prison.