Rescued passengers of the Norman Atlantic accident Marko Gondolo (2-L) and his daughter Serafina (2-R) arrive at the airport of Elefsina, west of Athens, Greece, 29 December 2014.
BRINDISI, Italy - The death toll from a ferry disaster in the Adriatic Sea rose to 13 on Tuesday as fears mounted that the final count could be much higher.
Uncertainty over the scale of the tragedy persisted with Greek and Italian authorities still unable to say with any certainty how many paying passengers were on board the Norman Atlantic when it burst into flames in stormy seas on Sunday.
And Giuseppe Volpe, the prosecutor in charge of a criminal probe into the disaster, said the discovery of stowaways among those rescued from the blazing ship meant "it is likely that we will find other victims in the wreckage".
Volpe&39;s comment suggested the navy had not been able to fully search the burnt-out ship. As well as the possibility of stowaways in some of the lorries on board, there were also fears some passengers may have suffocated or been burnt to death in their cabins.
The Italian coastguard confirmed the recovery of the body of an 11th dead passenger on Tuesday. The ill-fated Italian-owned ship claimed two more lives when two Albanian seamen died from injuries sustained when a cable linking their tugboat to the ferry snapped.
Nearly 40 passengers listed as having been on the ferry were still unaccounted for but it was unclear whether this was due to them having died as a result of the fire or by drowning, or the result of errors in the ship&39;s manifest.
Greek survivor Urania Thireou offered a possible explanation.
"At the start, there were people who got into the biggest lifeboat," she told AFP at a hotel in the Italian port city of Brindisi.
"They got it into the water but we were told afterwards that they were not rescued."
Amid the uncertainty over the passenger numbers, the Italian coastguard and navy helicopters continued to scour the waters around the stricken ferry, which caught fire after it left the Greek port of Patras bound for Italy.
- Missing passengers -
Officially, 437 people who were on board have been accounted for, 38 short of a revised total of passengers and crew released by the ship&39;s operator ANEK Ferries.
But government ministers in both Greece and Italy have confirmed that there are also significant discrepancies between the list released by ANEK and the people saved.
The ship&39;s Italian owner, ANEK and its Italian captain all face possible manslaughter charges arising from Volpe&39;s investigation. Greece also announced its own probe Tuesday.
The accounts of passengers evacuated from the ferry after a terrifying 24-hour ordeal have depicted the Norman Atlantic&39;s crew as being completely unprepared to deal with an emergency.
Many have told how it was either thick smoke or other passengers who woke those sleeping, not the crew or alarms.
Almost every survivor who has spoken about what happened has said they received no instructions from the crew about what to do.
Teodora Doulis, a Greek woman whose husband Giorgios died in the disaster, was among a number of passengers who described the car deck -- thought to have been where the fire started -- as being covered with fuel.
"It stank of petrol. The ship should never have left port in that condition," she said.
In the absence of leadership from the crew, the intensity of the fire, which made metal surfaces so hot that shoes were melting, led to a panic which exposed the worst side of human instinct, according to survivors.
Ute Kilger, a passenger from Munich, Germany, described how she had witnessed a middle-aged man barge past women, children and the elderly to ensure he was winched to safety before them.
"He just went and sat in the basket, which was clearly designed for children. I didn&39;t know whether to laugh or cry," the 45-year-old lawyer told Italian media.
- Safety inspection -
Two key questions for investigators will be why the fire gained such force so quickly and why it was not contained in the area where it started.
The ship&39;s owner, Italian company Visemar di Navigazione, has acknowledged that a December 19 safety inspection highlighted a problem with at least one fire door but insists it was fixed before the vessel set sail.
According to Paris MoU, a multi-national body which oversees maritime safety standards, the Greek inspectors highlighted problems with more than one fire door as well as the functioning of some water-tight doors, emergency lighting and the availability of life-saving equipment.
The deficiencies were all registered as having been addressed by the end of the day on which the inspection took place.
But Richard Schiferli, Paris MoU&39;s secretary-general, told AFP it was unclear whether all the problems had actually been fixed satisfactorily.