Search crews blasted holes into the wrecked Italian liner on Thursday to allow divers to continue a search for bodies, with time running out before the weather turns and salvage crews need to start pumping out the fuel tanks.

Six days after the 114,500 tonne Costa Concordia capsized off the Tuscan coast, hopes of finding anyone alive on the partially submerged hulk have all but disappeared and the cold waters around the ship have become noticeably rougher.

One of the specialist diving crews said on Thursday the available window could be as small as 12-24 hours although the chief spokesman of the rescue services denied that any deadline had been set and said the situation was still evolving.

The ship is a labyrinth. It's gigantic and it's lying on its side in the water. It's a miracle that so many survived, said Modesto Dilda, head of one of the diving teams.

Eleven people are known to have died out of more than 4,200 passengers and crew aboard when the ship struck a rock just metres from the shoreline, tearing a large gash in the side of the hull. As many as 24 are still unaccounted for. Two French passengers were identified among the dead on Thursday.

The ship's captain Francesco Schettino has been placed under house arrest, accused of causing the accident by sailing too close to the rocky shore and then abandoning ship before the evacuation was complete.

The ship's operators Costa Cruises, have suspended him and said they considered themselves the damaged party in the accident, which industry experts say could turn out to be the biggest maritime insurance claim in history.

On Thursday, SkyTG24 broadcast a tape of what was described as a conversation between coastguard officials and the bridge of the Concordia which appeared to show ship's officers telling authorities they had suffered only a blackout more than 30 minutes after the impact.

Italian media also devoted considerable attention to a female Moldovan crew member who was on board but not on duty. Several reports said she had been seen on the bridge with Schettino.

Mystery over the girl, was one headline, carried on the website of the Corriere della Sera. It said her presence on the bridge was inexplicable.

Was she a guest of the captain? And why was she not registered? Was she working without a contract?

In an interview with a Moldovan television station, the woman, 25 year-old Domnica Cemortan, recounted how she had survived the ordeal by thinking of her daughter and praised Schettino's extraordinary handling of the situation.

Many of my colleagues have the right to be angry, because now they have no work, they have to go home, they have children, debts to pay, all sorts of problems, she told JurnalTV.

Yet we all support the captain, because he has done something extraordinary: he has saved the lives of over three thousand people.

In a statement, Costa said she had embarked normally on January 13 in Civitavecchia and was properly registered.

SEARCH RESUMES

After interrupting the search on Wednesday when rescuers feared the vast liner was shifting on its resting place, crews resumed their search at first light on Thursday. They expect to blast three holes in the hull at about 20 metres depth.

An expected worsening of weather conditions in the next few days has added extra pressure on the diving teams to complete their search of the vessel.

Nothing was found in the morning during a search of the fourth deck, around an evacuation assembly point where seven of the bodies found so far were located but rescue workers continued operations after blasting new a way into the vessel.

It's important to continue our search. Family members find it important to have the body of the loved one they've lost because it gives them closure. We understand this, said Dilda.

Relatives of some of the French missing arrived on Thursday accompanied by consular officials but did not speak to reporters. One of the group appeared so upset that she had to be supported and helped into a church.

As hopes of finding survivors fade, attention has increasingly shifted to the threat of an environmental disaster in one of Europe's largest natural marine parks.

The ship is holding more than 2,300 tonnes of diesel and lubricating oil, and salvage crews are already preparing to begin pumping the fuel out of the wreck, a process that is expected to take at least two weeks.

Environment Minister Corrado Clini has warned there was a risk that with sea conditions expected to worsen, the ship could slip down 50 to 90 metres from the rock shelf it is resting on, further damaging the vessel.

He said ship operator Costa Cruises had been instructed to ensure steps are taken to limit the damage if the ship's fuel tanks rupture, including putting in place some 1,000 metres of pollution barriers.

LITTLE HOPE

The judge who placed Schettino under house arrest said he had shown incredible carelessness and a total inability to manage the successive phases of the emergency, only sounding the alarm 30 to 40 minutes after the initial impact.

He had abandoned the ship and remained on shore in a state of complete inertia for more than an hour, watching the ship sink, according to the ruling.

No serious attempt was made by the captain to return even close to the ship in the immediate aftermath of abandoning the Costa Concordia.

According to Schettino's lawyer, the captain has admitted bringing the ship too close to shore but he denies bearing sole responsibility for the accident and says other factors may have played a role.

The ship foundered after striking a rock as dinner was being served on Friday night. The owners say the captain swung inshore to take a bow to the islanders, who included a retired Italian admiral. Investigators say it was within 150 metres of shore.

Most of the passengers and crew survived despite hours of chaos and confusion after the collision. The alarm was raised not by an SOS from the ship but mobile phone calls from passengers on board to Italian police on the mainland.

(Additional reporting by Radu Marinas in Bucharest, Silvia Ognibene in Grosseto; Editing by Jon Boyle)