A 52-year-old woman is accused of slashing herself early Friday morning and then turning the blade on five other people, including three infants.
Victims at the home, in Flushing, Queens, were discovered around 3:30 a.m. local time.
The ages of two children, a boy and a girl, remains unknown but police say the girl is in a serious condition. None of the injuries are considered to be life-threatening, despite one of them being seriously hurt.
The man who was injured had a child at the day care while the woman was a daycare employee, according to NBC New York. Police say she had slashed her left wrist and is in custody at a hospital. Her relationship with the children wasn't immediately clear.
She was reportedly being treated at a hospital for a non-life-threatening wound.
The two adults were a co-worker at the facility and the father of one of the infants, the officer said.
Other children at the day care weren't injured, authorities said.