Italian divers have found a woman's body in the wrecked cruise liner Costa Concordia, raising the death toll from the maritime accident to 12.

Officials say the body was found Saturday in the corridor of a submerged section of the 114,000-ton ship and was transferred to mainland.

Divers had entered previously inaccessible parts of the ship below the water line after blowing holes in the side of the vessel with explosives.

Rescue efforts are continuing for 20 people still missing after the ship ran aground January 13 in waters off the Italian island of Giglio. Officials say hope of finding survivors after more than one week under water are slim. Authorities say they are also working to remove oil from the vessel to prevent an environmental disaster.

Italy's civil protection agency took command at the site Saturday after the government declared a state of emergency on the small Giglio Island. The agency's head, Franco Gabrielli, said that contamination of the surrounding area has already begun.

” I would like this to be clear: this is not an event where nothing happened. This is a story where a 300-meter-long ship carrying 4000 people on board, plus all these people needed (crew members), is in the sea. So the contamination of the environment, gentlemen, has already occurred.”

Gabrielli says 2400 tons of fuel are inside the shipwreck and needs to be removed.

The vessel, which is owned by U.S.-based Carnival Corporation, ran into a rocky reef, which damaged its hull, and caused the vessel to keel over on its side. The ship's captain, Francesco Schettino, has been accused of manslaughter and abandoning the ship before all its passengers and crew were evacuated.

Carnival Corporation says it will conduct a comprehensive audit of all of its cruise lines to review safety standards and procedures following the Concordia accident.