A small commercial aircraft crashed in an isolated part of Patagonia, southern Argentina, killing all 22 people on board.

"We did not find anyone alive," said hospital director Ismael Ali, who took part in the rescue mission. "The plane is in charred fragments. Everything is burned and smashed to pieces."

Ali said a witness reported seeing a fireball crash into a field near his home in the foothills of the Andes, indicating a possible midair explosion.

The plane had earlier been reported missing on a flight between the southern cities of Neuquen and Comodoro Rivadavia, in Rio Negro province.

Horacio Farre, a spokesman for the private company Sol, which owned the plane, confirmed there were no survivors. He said the aircraft crashed around 45 minutes after takeoff. It issued a distress signal just before it went down.

The passengers on the Saab 340 twin-engine aircraft included 18 adults, one minor and three crew members, the company said, adding that an investigation is under way.