A handout from the Italian Guardia de Finanza shows the Costa Concordia, after the cruise ship ran aground and keeled over off the Isola del Giglio.
Two South Korean honeymooners were rescued Sunday from a cruise ship that hit rocks and keeled over off the west coast of Italy, but three were confirmed dead with dozens still missing.
Two French passengers and one Peruvian crew member have been confirmed killed, apparently after jumping into the chilly Mediterranean waters after the Costa Concordia hit rocks late Friday and began to keel over.
"This is a risky operation," Cosimo Nicastro, a spokesman for the coast guard, told reporters at the scene. "The ship is in waters that are 30 meters (100 feet) deep but it could slowly slip into the sea and sink completely."
"We are talking about 50 or 60 people who are still missing" off the island of Giglio in Tuscany, he said.
Earlier, the governor of nearby Grosseto, Giuseppe Linardi, and port officials said 41 people were still missing.
Nicastro said some survivors may not have been counted properly but that others could have been trapped in their cabins or in other areas below deck.
Investigators arrested the ship's captain on Saturday and were to begin analysing the "black box" recovered by rescuers, which logged all of the 291-metre long ship's movements as well as conversations between personnel.
The captain, Francesco Schettino, told Italian news channel TGCOM that the ship hit a rock that was not on the charts and that he had tried to save as many people as possible.
First officer Ciro Ambrosio was also arrested, local prosecutors said.
Italian media said the two face possible charges of multiple homicide and abandoning the ship before all the passengers were rescued.
The captain "approached Giglio Island in a very awkward way, hit a rock that stuck into its left side, making (the boat) list and take on a huge amount of water in the space of two or three minutes," a prosecutor told reporters.
Island residents also said the ship was sailing far too close to Giglio and had hit an underwater rocky reef that was well known to the local population of the picturesque hilly outcrop, which has a population of just 800 people.
There was relief though early Sunday when a South Korean couple on their honeymoon, both aged 29, were rescued by firemen from a lower deck of the Costa Concordia where they had been trapped, Italian news agency ANSA said.
They had boarded the ship on their first-ever cruise at Civitavecchia, further south on the Italian coast.
The couple had been stranded two decks below rescuers on the half-submerged ship as the search for the dozens of missing out of more than 4,200 originally on board was continuing late into the night.
Rescue workers who had heard them calling for help took 90 minutes to extract them from their cabin.
The Korean couple were in good health and able to walk off the firemen's boat onto Giglio, where an ambulance took them away for medical checks, ANSA said.
Rescuers said they plucked 100 people from the sea in the night between Friday and Saturday after some of the lifeboats on board failed to function or could not descend to the water from a ship that was already badly listing.
About 60 people who had not managed to escape in lifeboats were rescued from the vessel itself, including one passenger with a broken leg.
Some crew members familiar with the layout of the ship were helping divers negotiate their way around the Italian-built liner's 1,500 cabins.
Survivors from around the world -- many of them with bloodshot eyes and draped in woollen blankets in Giglio harbour -- spoke of scenes "like the Titanic" on board and said they were not properly informed about the evacuation.
Some of the survivors were in evening wear as they had just been settling down to supper on board when the accident happened. There were also bar and restaurant staff in crimson blazers and kitchen staff in white smocks.
"We were lucky we were so close to the shore. Thank God. Everyone was very afraid," said Jose Rodriguez, a 43-year-old barman from Honduras, who was standing in line to receive food and clothing from emergency officials.
Officials said all the survivors had been taken off the island on Saturday to nearby Porto Santo Stefano and then on to other parts of Italy or back home.
The people on board included some 60 nationalities and some 52 were children under six. Nearly a third of the passengers were Italian, followed by Germans and French. There were also Americans, Russians and Japanese on board.
The Philippines said 300 Filipino crew members had been aboard the vessel.
The British and French ambassadors visited the scene of the accident, along with diplomatic officials from more than a dozen countries.
They privately expressed frustration over a lack of information about their citizens and on the handling of the ship's evacuation.
At least 42 people were injured, including two seriously -- a woman with a blow to the head and a man struck in the spine, medical sources said.
Most of those hospitalized had suffered broken limbs or had hypothermia.
The disaster happened just hours after the ship had left the port of Civitavecchia near Rome at the start of a Mediterranean cruise that was meant to take it to Savona in northwest Italy and then on to Marseille and Barcelona.
An executive with the Genoa-based company that owns the cruise ship insisted the vessel had not strayed off course.
"It is not correct to say that the boat was off its route," said Gianni Onorato, managing director of Costa Crociere.
The company is the biggest cruise operator in Europe, with a turnover of 2.9 billion euros ($3.7 billion) in 2010, according to its website.