A woman was dangling her two-year-old son over a railing at the Cleveland zoo when he fell about three metres into a cheetah exhibit, zoo officials said.

The toddler's parents jumped in and pulled him to safety Saturday afternoon. He was treated at a hospital for a few bumps and bruises, said Cleveland Fire Department spokesman Larry Gray.

The cheetahs didn't go toward the boy or his parents, said Chris Kuhar, executive director of Cleveland Metroparks Zoo.

Several eyewitnesses saw the woman holding the child over the railing, Kuhar said in a statement. "While this incident is disturbing to everyone, we are glad injuries were not any more severe," he said.

Cleveland Metroparks plans to seek child endangering charges against the mother on Monday, he said.

A similar incident at a Pittsburgh zoo left a two-year-old boy dead in 2012. The child was fatally mauled after falling into a wild African dogs exhibit.

The boy had lunged from his mother's grasp and fell about three metres from the top of a wooden railing into the enclosed exhibit below.

The boy's parents sued the zoo, saying it had been warned about other parents who routinely lifted children onto the railing. The zoo countersued, arguing the boy's mother was to blame for his death, because she lifted him atop the railing so he could get a better look into the exhibit.

The legal dispute was settled last year.