Authorities said 36 survivors were pulled from the wreckage of the French-built ATR-42 plane owned by Venezuela's state-run airline Conviasa.

The plane was flying from the Caribbean island of Margarita to the southern industrial city Puerto Ordaz when it came down near the gates of the vast Sidor mill on the banks of the Orinoco River.

Workers and firemen from the plant ran to the crash site and pulled passengers from the twisted and charred fuselage, one steel worker told state television.

A nearby Puerto Ordaz hospital received injured people and bodies from the crash site. Hospital director Yanitza Rodriguez said many of the injuries were serious.

An official at the National Civil Aviation Institute said the pilot had radioed in a mayday signal seconds before the plane crashed. "We presume (the accident) was caused by a failure in the airplane's controls," said the official, who asked not to be identified.

Reuters