Divers resumed their search Sunday morning for up to 50 people unaccounted for after a luxury Italian cruise ship ran aground off the coast of Tuscany, killing at least three people and injuring 20 others, authorities said.
There were fears the death toll could rise as rescuers searched the Costa Concordia and surrounding waters for others who may have been trapped after rocks tore a gash in the hull Friday evening, causing it to turn over on its side off the coast of the island of Giglio.
The ship's captain, Francesco Schettino, was detained later Saturday for investigation of manslaughter, causing a shipwreck and abandoning ship while passengers were still on board, chief prosecutor Francesco Verusio told Italy's ANSA news agency.
Verusio also said first officer Ciro Ambrosio also was being detained for questioning on similar charges, according to ANSA.
Rescuers overnight reached two South Korean passengers, who had been trapped in the ship for more than 24 hours, authorities said.
"It's a miracle that we found the Korean couple alive, and we hope we'll find more people," said Capt. Cosimo Nicastro of the Italian Coast Guard.
The couple, both age 29, were found in a cabin after they heard rescuers calling out and managed to make contact, according to ANSA. Video showed the couple, reportedly on their honeymoon, being taken ashore and loaded into a waiting ambulance.
Up to 50 people were missing, though authorities are reviewing passenger lists to confirm the exact number, said Giuseppe Orsina, a spokesman with the local civil protection agency.
"These people could be still on the island of Giglio, in private houses or in hospitals," Orsina said.
Two French tourists and a crew member from Peru were killed, Port authorities in Livorno said. One of the victims was a 65-year-old woman who died of a heart attack, authorities said.
As dawn broke over the azure waters where the Concordia was partially submerged, there were more questions than answers about how the 1,500-cabin ship managed to strike rocks during its oft-traveled route, and who was responsible for the chaotic scene that followed the captain's orders to evacuate the ship.
The Concordia was 2.5 miles off route when it struck the rocky sandbar near Giglio, said Nicastro.
"There are rocks, they are on the maps," Nicastro said. "What we know is the ship went really close to these rocks. ... We don't yet know why."
The ship began taking on water Friday night, and the crew kept going because they believed the vessel could continue sailing normally, Nicastro said. Realizing there was a significant safety problem, the commander steered the Costa Concordia closer toward the port of Giglio, he said.
Authorities also were looking at why the ship didn't hail a mayday during the accident.
Local fishermen say the island coast of Giglio is known for its rocky sea floor.
Schettino, the Concordia's captain, said in an interview before his detention that "that rock was not indicated on the chart," according to ANSA. "Me and the crew, we were the last to abandon ship," he said.
But accounts from many of the 3,200 passengers painted a chaotic, dangerous scene as people scrambled to find lifeboats in the dark as the ship began to tilt, hampering access to some of the lifeboats.
"For me, the worst part of the whole ordeal" was when a lifeboat crew member told those boarding that it was "women and children first," said passenger Benji Smith of Boston.
"All these families who were clinging to each other had to be separated," Smith told CNN.
"Every crew member who walked past shouted instructions, but the instructions contradicted each other."
Some passengers fell into the chilly waters during the rescue, ANSA reported.
Others jumped in, said passenger Mark Plath of Little Rock, Arkansas.
Plath told CNN he and about 200 passengers swam about 100 yards from the ship to the rocky shoreline, where they awaited further assistance.
Many of those rescued in the early hours were taken to small churches and other buildings around the island for shelter. Some were still wearing the pajamas and slippers they had on as the ship went down.
Gianni Onorato, president of Genoa-based Costa Cruises, said the cruise line was unable to answer all the questions that authorities are now investigating.
The vessel, plying the waters from Civitavecchia to Savona, Italy, struck a submerged rock, Onorato said in a statement Saturday before the captain's arrest was announced.
"Captain Schettino, who was on the bridge at the time, immediately understood the severity of the situation and performed a maneuver intended to protect both guests and crew, and initiated security procedures to prepare for an eventual ship evacuation," he continued.
"Unfortunately, that operation was complicated by a sudden tilting of the ship that made disembarkation difficult," Onorato said.
Rosalyn Rincon, a member of the cruise ship staff, said the captain told passengers there was an "electrical problem."
Concordia was carrying about 3,200 passengers and 1,000 crew members when it ran aground.
Costa Cruises, owned by parent company Carnival Corp., said it was focusing on the final stages of the emergency operation and helping passengers and crew return home.
The Concordia, built in 2006, was on a Mediterranean cruise from Rome with stops in Savona, Marseille, Barcelona, Palma de Mallorca, Cagliari and Palermo.
The passengers onboard included Italian, Peruvians, Brazilians, French and Britons, according to CNN affiliate reports.
An estimated 126 Americans were also onboard, according to the U.S. State Department. There were no reports of injured Americans, though the U.S. Embassy in Rome said it was unable to account for all U.S. citizens believed to be onboard the ship at the time of the accident.
Another Costa ship was involved in a deadly 2010 accident when the Europa crashed into a pier in Egypt's Sharm el-Sheikh during stormy weather, killing three crew members.