The body of a woman has been found on board the Italian cruise ship that ran aground and capsized a week ago, bringing the known death toll to 12, BBC reported.

The woman, who was wearing a life jacket, was found by divers on the fourth deck of the Costa Concordia.

Twenty people are still missing after the ship, with 4,200 people on board, struck a rock in shallow waters on 13 January off Tuscany's Giglio island.

The captain is being investigated for manslaughter, which he denies.

An unnamed police official said the woman's body was found at around 13:30 (12:30 GMT) and was taken to the mainland.

"They will have to rely on DNA tests now to identify the victim after a week in the water," he told AFP news agency.

Coastguard and navy divers resumed their search on Saturday, blasting their way into submerged areas of the vessel using explosives in an effort to find those unaccounted for.

Coast Guard spokesman Cosimo Nicastro said the body was found during a particularly risky search of an evacuation meeting point near the rear of the ship.

"The corridor was very narrow, and the divers' lines risked snagging'' on objects in the passageway, Cmdr Nicastro said.

Rescue officials on Saturday said they would not end the search until the whole ship had been examined.

But correspondents say they are under time pressure, amid fears the ship could slip off a ledge into deeper water.