WASHINGTON, July 17 (Xinhua) -- At least three people were killed after two small planes collided mid-air in the U.S. state of Florida Tuesday, authorities said.

The accident took place in southern Florida, the Federal Aviation Administration said. Local police have confirmed that three people have been killed and the whereabouts of a possible fourth passenger is unknown.

The police have yet to identify the victims, but the planes were believed to be piloted by flight instructors, one of which is reportedly a 22-year-old Jorge Sanchez.

Miami Dacde County Mayor told local media that both planes belonged to Dean International, a flight school that has a history of more than two dozen incidents and accidents in the last decade.