A 6-month-old girl is dead and her mother is in serious condition after a tree branch fell on the pair as the father tried to take a photo during a visit to the Central Park Zoo, according to NYC officials and NYPD sources familiar with the freak accident.

The child’s 33-year-old mother is at Weill Cornell Medical Center on the Upper East Side in serious but stable condition.

The accident happened just before 2 p.m. Saturday while families were enjoying the crowded zoo on a hot summer day. As the father prepared to take a photo of his wife, who held their daughter in her arms, witnesses heard a snap, NYPD sources tell NBCNewYork.

Everyone screamed and the branch fell about 40 feet, striking both the mother and baby in the head before crashing to the ground and splitting in half, according to people at the scene.

The Union City, N.J., family was visiting the park with another couple who also had kids, NYPD sources said.

The child was pronounced dead at Weill Cornell after being taken there by ambulance. The name of the victim has not been released. 

A city source tells NBCNewYork the tree was within jurisdiction of the zoo, which is maintained by the Wildlife Conservation Society.

A Wildlife Conservation Society spokesman declined comment.

This is the second victim of a tree branch at the zoo this year. In February, a man was killed in the park when a snow-covered branch snapped from a tree and slammed onto his head. Last July, another man was critically injured in a separate incident.

(Source: NBC New York)