The operators of the Costa Concordia faced questions over their share of the blame for the shipwreck, as divers recovered another body from the stricken liner on Sunday, bringing the known death toll to 13.

Captain Francesco Schettino is accused of steering the 290 metre-long cruise ship too close to shore while performing a manoeuvre known as a ‘salute’ in which liners draw up very close to land to make a display.

Schettino, who is charged with multiple manslaughter and with abandoning ship before the evacuation of its 4,200 passengers and crew was complete, has told prosecutors he had been instructed to perform the manoeuvre by operator Costa Cruises.

Prosecutors say he steered the ship within 150 metres of the Tuscan island of Giglio, where it struck a rock that tore a large gash in its hull, causing it to keel over.

It is now lying on its side on an undersea ledge, half-submerged and in danger of sliding into deeper waters.

As the search continued into a ninth day, divers found the body of a woman on a submerged deck near the bow of the vessel, bringing the total number of known dead to 13, only eight of whom have been identified.

‘Ship owners insisted on salute’

Costa Cruises have said they were not aware of any unsafe approaches so close to the shore and have suspended Schettino, saying he was responsible for the disaster.

According to transcripts of his hearing with investigators, Schettino has disputed that claim, saying Costa had insisted on the manoeuvre to please passengers and attract publicity.

"It was planned, we should have done it a week earlier but it was not possible because of bad weather," Schettino said.

"They insisted. They said: 'We do tourist navigation, we have to be seen, get publicity and greet the island'."

Italian newspapers have also published photographs of the Costa Concordia apparently performing the ‘salute’ close to other ports including Syracuse in Sicily and the island of Procida, which is near Naples and Schettino's hometown of Meta di Sorrento.

Schettino also said the black box on board had been broken for two weeks and he had asked for it to be repaired, in vain.

‘Did not want to create panic’

In the hearing, Schettino insisted he had informed Costa's headquarters of the accident straight away, and his line of conduct had been approved by the company's marine operations director throughout a series of phone conversations.

He acknowledged, however, not raising the alarm with the coastguard promptly and delaying the evacuation order.

"You can't evacuate people on lifeboats and then, if the ship doesn't sink, say it was a joke. I don't want to create panic and have people die for nothing," he said.

Costa, a unit of Carnival Corp (CCL.N), the world's largest cruise line operator, says Schettino lied to the company and his own crew about the scale of the emergency.

Documents from his hearing with a judge say he had shown ‘incredible carelessness’ and a ‘total inability to manage the successive phases of the emergency’.

Taped conversations show ship's officers told coastguards who were alerted by passengers that the vessel had only had a power cut, even after those on board donned lifevests.

Unregistered passengers?

Adding to the growing debate about the ship's safety standards, Franco Gabrielli – head of Italy's Civil Protection authority, which is coordinating the rescue operations – said a number of unregistered passengers may have been on board.

Relatives of a missing Hungarian woman told authorities she was on the Costa Concordia with a member of the crew, but her name was not on the list of passengers, he said.

"In theory, there could be an unknown number of people who were on the ship and have not been reported missing because they were not registered," Gabrielli said.

20 people still missing

Of the 13 bodies found, only 8 had been identified – four French nationals, an Italian, a Hungarian, a German and a Spaniard. At least 20 people are still unaccounted for.

Minor pollution from detergents and disinfectants aboard the shipwreck had been detected in the waters around the vessel but there was no sign that the heavy fuel in its tanks was leaking, Gabrielli said.

He said tests were being carried out daily on the waters around the ship and a nearby desalination plant that provides drinking water for the island's residents.

"The tests for toxic substances are negative so far," Gabrielli said. "The only significant elements detected, which luckily are not worrying yet, relate to ... detergents and disinfectants used on the ship, for the swimming pool or to clean the bathrooms for example."

Environment experts have warned that contamination of the pristine waters around Giglio, which is in the middle of a national marine park, is already under way and it is imperative to start recovering the fuel oil as soon as possible.