Twenty one people have been injured after a plane caught fire on a runway at Chicago's O'Hare International Airport.

Pilots of the Boeing 767 jet were forced to evacuate passengers from the burning American Airlines flight bound for Miami yesterday afternoon.

A federal official has put it down to an 'uncontained engine failure'.

An investigation's due to take place.

American Airlines said in a statement: "Twenty passengers and one flight attendant reported non-critical injuries. Several were transported to Chicago-area hospitals to be evaluated. 

"Members of American's specially trained employee volunteer CARE Team have been mobilised and dispatched to those hospitals, and Chicago O'Hare International Airport to provide assistance for our customers, crew members and their families."

The statement added: "We are operating a special flight tonight to take our customers to Miami."

Timothy Sampey of Chicago's Fire Department said the mishap could have been much worse.

The plane was fully loaded with 43,000lbs (19,504kg) of jet fuel, which was leaking when fire crews reached the jet, he told a news conference.

"So they had a heavy volume of fire on both the engine and the entire wing," he said. "This could have been absolutely devastating if it happened later."