All six passengers have been killed on a medical plane that crashed in a Philadelphia neighbourhood on Friday night, including a mother and her daughter, according to the mayor's office.

Philadelphia Mayor Cherelle Parker adds that "many people on the ground" were injured as homes and fires in the areas were ablaze in the aftermath.

The medical transport plane was taking the girl - who had been receiving care in the US for a life-threatening condition - back to Tijuana, Mexico. Four crew members were also on board.

Flight logs show the plane was in the air "for only a minute before it crashed."

In an audio recording obtained by CBS News, the BBC's US partner, an air traffic controller can be heard saying they're "not exactly sure what happened."