The known number of lives lost in the grounding of that Italian cruise ship has risen to 13 after divers on Sunday removed the body of a woman from the stern of the Costa Condordia.

On Saturday, the body of another woman was retrieved. Both of the women were said to be wearing life vests. They, along with most of the other victims of the January 13 disaster, have not been identified.

As many as 20 people, most of them passengers, remain missing. There is also concern that some unregistered passengers may have been on board.

The 114,000-ton ship has been slowly shifting on the reef where it is resting off the Italian island of Giglio, causing concern and making the recovery efforts more difficult. There is also concern that the nearly 2,500 metric tons of fuel on board could start spilling into the sea, raising the possibility of an environmental disaster.

On Saturday Italian authorities declared a state of emergency on the small island.

The captain of the cruise ship, Francesco Schettino, remains under house arrest, accused of manslaughter and abandoning the vessel.