A Greek prosecutor on Saturday charged the captain of the sunken Sea Diamond cruise ship with negligence after the vessel foundered off an island in the Aegean Sea, an official said.
The search for two missing French passengers continued. The rest of the 1,154 passengers and 391 crew were safely evacuated after the ship hit rocks on Thursday and started to list.
The Greek captain was charged with causing a shipwreck through negligence, breaching international shipping safety regulations and polluting the environment, a Merchant Marine Ministry spokeswoman said.
But she said she could not confirm a report on state NET TV that five other officers who had been questioned had also been charged. She spoke anonymously in accordance with government practice.
She said the captain and the five other officers, who had been arrested after the accident, appeared before a prosecutor on the nearby island of Naxos on Saturday and have been released pending further investigations.
If upheld in court, the charges against the captain would mean up to a five-year sentence.
The ministry spokeswoman said the other officers questioned were chief mate, second mate, third mate, chief cabin steward, and housekeeper of the Greek-flagged vessel.
All six are Greek nationals, the cruise company, Greece-based Louis Hellenic Cruises, said. The company had no comment on the charges, and did not release the suspects' names.
The 143m vessel hit a well-marked and charted reef in fair weather inside Santorini's sea-filled crater.
The ship had been due to dock a few minutes later.
The sinking vessel was evacuated in a three-hour rescue operation, but Jean-Christophe Allain, 45, and his 16-year-old daughter, Maud, from Doue-la-Fontaine in western France were later listed as missing, feared to have been trapped in their flooded lower-deck cabin.
The ministry spokeswoman said the search for the two continued, while divers continued to investigate the hulk of the Sea Diamond.
Officials were also carrying out a clean-up effort for fuel that had leaked out of the 21-year-old vessel, which sank 15 hours after the accident.
"The vessel maintained the highest level of safety standards and was equipped with the latest navigation systems," said Giorgos Stathopoulos, spokesman for the ship's Cyprus-based operator, Louis Cruise Lines.
The ship underwent its last annual survey on March 9, and had been issued safety management and security certificates by Norway's Det Norske Veritas ship classification society, a DNV press release said.
Thursday's evacuation was the largest Greek rescue operation since the September 2000 Express Samina ferry disaster, which killed 80 people near the holiday island of Paros when it struck rocks in the night and sank.
It also created a major headache for officials in Greece's key tourism industry -- which accounts for an estimated 18 percent of the country's GDP.
"Whoever is responsible for this will be held accountable in the strictest way," Tourism Minister Fanny Palli Petralia said. "Greece is a major tourism destination and incidents like this must not be allowed to occur. ... Authorities handled the rescue very well."