The vast wreck of the cruise ship Costa Concordia shifted on its undersea ledge today, forcing a new suspension of rescue work and threatening plans to pump oil out to prevent environmental disaster.
Firefighters' spokesman Luca Cari said rescue squads would be discussing the next step after the movement made conditions unsafe for divers already hampered by poor visibility, floating objects and underwater debris.
Seven days after the 114,500-tonne ship ran aground and capsized off the Tuscan coast, hopes of finding anyone alive have all but disappeared and the cold waters around the ship have become rougher, with worse weather expected at the weekend.
"The ship is slipping about 15 millimetres at the front and seven millimetres an hour at the back. This is not a lot but it has to be kept under control," Nicola Costagli, a geophysics professor who is a consultant to the civil protection department, told SkyTG24 television.
Attention is now turning to how to remove more than 2,300 tonnes of fuel aboard the vessel, which lies on its side on a rock shelf in about 20 metres of water off the little island of Giglio and which could slide off its resting place.
Costagli said the ship was resting on two rocky protrusions, adding "we have to establish if these two points of support are stable".
Salvage crews are waiting until the search for survivors and bodies is called off before they can begin pumping the fuel out of the wreck, a process expected to take at least two weeks.
Environment Minister Corrado Clini told parliament today he had instructed the liner's operator, Costa Cruises, to take all possible measures to anchor the ship to prevent it from slipping further into the sea.
"If the ship slides, we hope that it doesn't break into pieces and that the fuel tanks do not open up," he said.
Clini said there was a risk that the ship could sink to 50 to 90 metres below the rock ledge on which it is caught, creating a major hazard to the environment in one of Europe's largest natural marine parks.
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, although that number probably includes bodies found but not yet identified.
Rescue workers are still looking for a missing five-year-old girl and her father.
The ship's captain Francesco Schettino has been placed under house arrest, accused of causing the disaster and then abandoning ship before the evacuation was complete.
His lawyer says he has admitted bringing the ship too close to shore but denies sole responsibility and says other factors may have played a role in the accident.
The ship's operators 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.
Yesterday, SkyTG24 broadcast a tape of what was described as a conversation between coastguard officials and the bridge of the Concordia which appeared to show officers telling authorities they had suffered only a power cut, more than 30 minutes after the ship's impact with the seabed.
In an interview with the daily Corriere della Sera, the chief executive of Costa Cruises criticised Schettino for delaying the order to evacuate and denied that he had faced pressure to wait because of the potential cost to the company.
"I assure you absolutely that no one thought in financial terms. That would be a choice that would violate our ethics," he said. He denied knowledge of captains sailing dangerously close to shore to provide a spectacle for passengers.
"I can't rule out that individual captains, without informing us, may have set a course closer to land. However I can rule out ever having known that they may have done it unsafely," he said.
The Italian cabinet was to discuss new regulations on Friday to prevent big cruise ships from taking risky routes and passing too close to islands or shorelines.