Divers recovered another body from the wreck of the Costa Concordia yesterday, as officials expressed fears that unregistered passengers meant they could not say exactly how many were missing.

Divers pulled a woman’s body from the cruise liner, recovered from deck seven at the stern of the ship, which brought the death toll to 13.

But with divers looking for some 20 officially missing, the head of Italy’s protection agency, Franco Gabrielli, warned that there may have been people on board who were not registered on crew or passengers lists.

Relatives of a Hungarian woman have claimed she telephoned them from the ship but there was no official record that she was ever on board, said Mr Gabrielli.

“Passengers may have been invited on board at the last minute by a crew member,” the agency’s spokesman Francesca Maffini said later. But the ship’s purser Manrico Giampedroni told Ansa news agency that it was “impossible there were clandestine or unregistered people” on board.

“They are registered and photographed on boarding. It’s all electronic. The Costa is a serious company,” he insisted.

Sources have suggesed that since the luxury liner hit rocks just two hours after setting sail from Civitavecchia, staff might not have had time to add the names of last-minute passengers to the relevant lists. Families waiting for news of missing loved ones attended a special remembrance mass on Giglio Island yesterday.

“This is a moment for hope, trust and faith,” Priest Lorenzo Pasquotti, who sheltered passengers in the St Lorenzo church in the hours after the disaster.

“Nothing happens for no reason. Those who are suffering can share their burden with God,” he said, urging relatives of missing French and Peruvian victims not to give up hope. Nine days after the luxury Costa Concordia crashed into rocks off Giglio Island with 4,229 people from 60 countries on board, fresh reports of the captain’s account of the tragedy emerged.

Francesco Schettino fiercely denied abandoning ship after the boat hit rocks, in excerpts from a 135-page statement he gave to Italian prosecutors published in the Italian media yesterday.

He had lost his footing and fallen off as the vessel lurched onto its side, he said.

“Me, a coward? A vile person that ran away? I had no life-jacket that night, because my life, from that night, was not worth anything,” he told prosecutors in excerpts of the statement published by the daily La Repubblica.

But he admitted he had made it to the shore aboard a motorised lifeboat which was difficult to steer and which may have run over people as they floundered in the water.

“It might even be that some people’s heads were hit,” he told prosecutors, in La Repubblica reported.

Mr Schettino said he had sailed near the island to “salute” its residents.