Three people, including a toddler, were killed and another was injured in a shooting that broke out over what officials say was the apparent sale of a dog at a Florida apartment complex.

Deputies responded to a report of shots fired just after 10 p.m. Saturday and found two adults and a 3-year-old child killed, and another adult injured, Jacksonville Sheriff’s Office Assistant Chief J.D. Stronko said.

Five people, including the child, had travelled to the apartment complex to meet with someone about the private sale of a dog, though it wasn't immediately clear whether they were buying or selling a dog, Stronko told reporters overnight at a news conference.

"For reasons that are unknown to us at this time, a dispute ensued in a breezeway between two of the apartment buildings, resulting in four of the five individuals being shot," he said.

Three of the four adults in that group were in their 20s, he said.

Witnesses said they saw two men fleeing the scene in a car, and there was no more information available about the victims or suspects, Stronko said.

The sheriff's office didn't immediately respond to a request for more information Sunday.