Officials at the Pompeii archaeological site have announced the dramatic discovery of the skeleton of a man crushed by an enormous stone while trying to flee the explosion of Mount Vesuvius in 79 AD.

The man may have escaped the initial violence of Vesuvius in the ancient city of Pompeii, only to be crushed by a block of stone hurtling through a lethal volcanic cloud.

Photos released on Tuesday show the skeleton protruding from beneath a large block of stone.

The stone is believed to have been part of a door frame that had been "violently thrown by the volcanic cloud", officials said.

Archaeologists working at the ancient site said the victim, who was at least 30 years old, had his thorax crushed in the impact.

The man is believed to have suffered an infection of the tibia, impeding his escape. ( Ciro Fusco/ANSA via AP )

The victim's head has not yet been found.

Officials said the man suffered an infection of the tibia, which may have caused walking difficulties, impeding his escape.

The archaeological site's general director, Massimo Osanna, called it "an exceptional find" that contributes to a better "picture of the history and civilisation of the age".