Human error almost certainly contributed to the sinking of a cruise ship off Greece's island of Santorini on Friday, a Greek minister said.
The ship sank 15 hours after it ran aground on rocks
A remote-controlled submarine has been taking pictures of the Sea Diamond in the hope of finding two French passengers who are feared drowned.
Clean-up crews are working to prevent more oil spilling from the sunken ship.
Nearly 1,600 passengers and crew were evacuated from the Greek-flagged Sea Diamond when it ran aground, then sank.
The Sea Diamond's captain and five other crew have been charged with negligence.
"Most definitely there was also human error," said Greece's Merchant Marine Minister Manolis Kefaloyannis.
He said efforts were now focused on trying to find the two missing French tourists and on protecting the environment from the oil spilling from the sunken ship.
Pumps are sucking brown scummy oil from the surface of the Aegean Sea, says the BBC's Malcolm Brabant on Santorini.
Workers are in boats trying to remove thick oil from the harbour wall at Athinios, the island's main port, he adds.
Special vessels are trying to pump the remaining oil from the ship's tanks.
Santorini is a volcanic island with steep cliffs that is one of Greece's most popular tourist destinations.
The residents depend almost entirely on tourism and are holding their breath to see whether people are scared away by the sinking at the beginning of the summer season, our correspondent says.
The captain has told investigators that a current took him by surprise and swept the boat onto well-marked rocks just before it was to dock at Santorini's harbour.
The three-hour evacuation was criticised by some passengers as slow and chaotic.
Officials have named the missing pair as Jean-Christophe, 45, and his daughter Maud Allain, 16, from Doue-la-Fontaine in western France.
They were in a four-berth cabin when the vessel struck a reef. Mr Allain's wife and son narrowly managed to escape to the upper decks. About half the passengers were Americans, with the rest from Spain, France, Germany, Britain and elsewhere.
The 143-metre (469 ft) cruise ship, built in 1986, is owned by Cyprus-based Louis Cruise Lines.