A 2-month-old baby and the child's mother were attacked by a pit bull in Elmont just after noon on Thursday, police said.
The 36-year-old woman had brought her child to visit a friend, officials said. The dog lunged at them after the woman rang the doorbell.
It bit the woman's legs, causing severe lacerations, and then attacked the baby, biting the child's head, police said. Neighbors heard screaming coming from the apartment during the attack.
"I was standing outside, I heard the mother crying 'my baby, my baby,'" Myrlande Alovidor said.
People in the area pulled the pit bull off the baby boy and called 911.
The baby had surgery for the wounds. He and his mother are both still in the hospital with serious injuries, Nassau County Police Detective Richard Lebrun said.
"The mother has very serious wounds to her legs," Det. Lebrun said. "And the baby had very, very serious wounds to the facial area and the cranium."
The mom and her baby live in the same building, but in a different apartment downstairs.
Two pit bulls live in the home, but only one - a 4-year-old male - attacked, police officials said. They are both at the Hempstead Animal Control Shelter.