The death toll from the sinking of the Costa Concordia has risen to 13, after divers found the body of a woman in the wreck of the cruise ship.

Italian fire service divers reportedly found the body on deck seven of the vessel, about 10 metres below the water line.

Rescue workers are still looking for 20 people who are believed to be missing.

The vessel sank on January 13 after hitting rocks near the island of Giglio, off Tuscany.

The woman who has now been found was wearing a life-jacket, officials say. Her body is being removed from the ship.

Only eight of the 13 bodies discovered have so far been identified. Four of the victims were French, one was Italian, one Hungarian, one Spanish and one German, officials say.

The identity of a woman whose body was found on Saturday has yet to be established, along with those of three men discovered previously.

The head of the Civil Protection Agency, Franco Gabrielli, said the woman may be a Hungarian who was reported missing but was not on the ship's embarkation list.

There could have been more "illegals" on board, he said, referring to people who were not registered to be on the vessel.

There were known to be 4,200 people on the cruise ship when it got into trouble.

The captain, Francesco Schettino, is being detained under house arrest while his actions are investigated.

He is accused of multiple manslaughter, causing a shipwreck, and abandoning ship before all passengers were evacuated. He denies the allegations.

Prosecutors say the 57-year-old was sailing too close to Giglio on an unauthorised course in order to perform a "salute" which is a greeting to islanders.