(REUTERS) -- Rescuers resumed a search of the hulk of a giant cruise liner off the west coast of Italy on Monday after bad weather forced them to halt operations, but hopes were fading of finding more survivors.
Worsening weather and heavy seas earlier made the wreck slip on the rocky underwater slope where it is lodged off the island of Giglio and rescue teams were evacuated. But they returned to work after several hours, seeking up to 16 missing people out of the 4,200 who were aboard. Six bodies have been found so far.
Firefighters' spokesman Luca Cari said there were still small movements but they were not considered dangerous. However, night-time searches would be suspended from now on.
Another senior firefighter, Luciano Roncalli, told Reuters that all the areas of the part-submerged liner that are above water had now been searched, indicating faint hopes of finding more survivors.
Earlier search teams recovered a sixth body from the 114,500-tonne Costa Concordia, which was holed by a rock late on Friday and rolled onto its side just off the coast of the picturesque port. The giant, multi-storey liner had about 4,200 passengers and crew on board, though some uncertainty about the numbers means it is unclear just how many are unaccounted for.
The vessel's captain, Francesco Schettino, was arrested on Saturday. He is accused of manslaughter and abandoning his ship before all those on board were evacuated.
The chief executive of the ship's owners, Costa Cruises, on Monday blamed human error by Schettino for the disaster. Pier Luigi Foschi told a news conference the company would provide its captain with any assistance he required. But we need to acknowledge the facts and we cannot deny human error, he added.
These ships are ultra-safe. It is an exceptional event, which was unforeseeable, he said, fighting back tears.
The calm weather which since Friday has aided the rescue and search of the wreck, one of the biggest ever of a passenger ship, took a turn for the worse with rougher seas and a light drizzle falling. Forecasters said worse was coming.
A salvage expert on Giglio, who asked not to be named, told Reuters the ship was clearly moving after being held in place by sharp points of rock that had pierced the hull. Rougher seas could break it free, which would be a big problem, he said.
Cari of the fire brigade said the rescuers could hear no noises from possible survivors inside the half-submerged ship.
Obviously the more time passes, the less possibility there is of finding anyone alive, he said.
Cruise company chairman Foschi said Schettino's actions had caused the accident and were contrary to company rules. The captain denies being too close to the coast and says the rock he hit was not marked on charts.
His lawyer, Bruno Leporatti, said Schettino was overcome and wants to express his greatest condolences to the victims.
But he said Schettino's actions in anchoring the ship at one end to swing it closer to the shore after the collision, saved the lives of thousands of people.
It could have been an enormous tragedy, Leporatti added.
The United Nations' shipping agency, the International Maritime Organization, said it was important not to pre-judge the outcome of an inquiry but said it would examine changes to regulations if these were shown to be necessary.
Recalling the sinking of the Titanic in April 1912, IMO Secretary-General Koji Sekimizu said: In the centenary year of the Titanic, we have once again been reminded of the risks involved in maritime activities.
The disaster occurred as passengers were sitting down to dinner on Friday night, triggering panic with thousands jostling to get on lifeboats and some leaping into the icy sea.
Investigators say the vessel was much too close to the shore and residents say its course was much nearer land than usual.
The father of the ship's head waiter told Reuters that his son had telephoned him before the accident to say the crew would salute him by blowing the ship's whistle as they passed close by Giglio, where the both the waiter, Antonello Tievoli, and his 82-year-old father Giuseppe live.
The ship obviously came too close, the elder Tievoli said. I don't know if Antonello asked the captain to come near, but the responsibility is always the captain's.
Passengers say there were long delays in sending an SOS and organizing the evacuation of those on board and this had resulted in chaos. More than 60 people were hurt.
Italian passengers told newspapers they used their mobile phones to call the Carabinieri police in the city of Grosseto on the mainland to raise the alarm, while the crew were still insisting to them that there was only an electrical fault.
Three people, a South Korean honeymoon couple and a crewman, were rescued on Sunday and police divers also found the bodies of two elderly men, still wearing life vests. The bodies of two French tourists and a Peruvian crewman were found on Saturday.
The vast hulk of the 290-metre vessel, lying on its side, loomed over the little port of Giglio, which sits on the island of the same name in a maritime nature reserve off the Tuscan coast.
A large gash could be seen in its hull but salvage experts said its fuel tanks did not appear to have been damaged, lessening the danger of an oil spill in the pristine waters.
A sixth body, that of an adult male passenger, was recovered just before dawn on Monday, officials said.
Giuseppe Linardi, the national government prefect for the province of Grosseto, told reporters the number of those unaccounted for stood at 16 but that could change slightly as passenger lists were rechecked.
He said efforts to prevent an environmental disaster would have to wait until the rescue was over. The worsening of the weather could create a critical situation, he said.
Environment minister Corrado Clini told reporters: The environmental risk for the island of Giglio is very, very high.
Workers from Dutch salvage company Smit said equipment to pump fuel off the stricken liner was being sent by barge but the operation would depend on it remaining stable.
The ship is resting in about 20 meters (60 feet) of water but could go down by up to 130 meters if it becomes detached from the rocks.
Investigators were working through evidence from the equivalent of the black boxes carried on aircraft to try to establish the precise sequence of events behind the disaster, which occurred in calm seas and clear weather.
Carnival Corp, the ship's parent company, said it estimated the impact on its 2012 earnings for loss of use alone to be around $90 million. Its share price was down around 16 percent on the London market.
Italy's defense minister, Giampaolo Di Paola, who is also an admiral, said the disaster did not appear to have been caused by natural or technical factors.
In my estimation there was a serious human error, which had dramatic and tragic consequences, he told RAI state television.
Prosecutors accused Schettino, who has worked for Costa Cruises since 2002 and who was promoted to captain in 2006, of refusing to return to the vessel when asked by the coastguard.
Schettino said the ship hit rocks that were not marked on maps and were not detected by navigation systems. He said the accident occurred some 300 meters (yards) from shore.
There was deep anger in Italy about the accident.
In a frontpage editorial for the respected daily Corriere della Sera, Pierluigi Battista wrote: Italy owes the world, international public opinion, the families of those who lost their lives, those who were injured and those who fortunately remained unhurt, a convincing explanation and the toughest possible sanctions against those responsible for this tragedy.