The discovery leaves about 16 people still missing from among the roughly 4,200 aboard the cruise liner -- about 3,200 passengers and 1,000 crew members -- at the time of the collision with rocks off the island of Giglio.
The vast majority fled the ship safely, if under chaotic and frightening conditions, according to survivors.
Undersea salvage experts will not start siphoning fuel off the partially sunken liner before Saturday, the man in charge of the operation said Tuesday.
Teams of divers have begun to set up the operation, Franco Gabrielli said in remarks televised from Giglio.
His comments appear to contradict a timetable laid out Monday by an Italian admiral, who said that salvage workers were to begin pumping fuel out of the liner that day.
Adm. Ilarione Dell'Anna said it would take 28 working days to remove all the fuel from the ship.
Gabrielli did not explain the discrepancy.
He has asked the company that owns the ship to come up with a plan to clean up pollution from the vessel, such as garbage, by Wednesday, he said.
The search for survivors and victims will continue alongside the salvage, said Gabrielli.
The man in charge of the rescue operation said the divers faced a grim task.
"Imagine that you left for holidays and that the power went off in your house. What would you find in your fridge? The divers are in there," Ennio Aquilino said.
Two bodies were found on Monday, and two more over the weekend -- one woman on Saturday and one on Sunday, both wearing life jackets.
Divers used explosives Monday morning to blow more holes in the side of the ship to allow easier access.
The parties involved in the rescue told reporters and residents on the island Sunday that search and rescue efforts will continue -- but that the environmental risk is also becoming urgent.
Officials said they cannot predict how long it will take to clear the wreckage, since that depends on maritime conditions and technical difficulties, but all legal, environmental and human factors will be taken into account.
"It's time for Italy to show it can do something right and do it well," said Gabrielli.
He warned that the task ahead was complicated and daunting, not least because it takes about 45 minutes to search each cabin, using special cameras and divers.
The giant Costa Concordia had 1,500 cabins on board.
A class-action lawsuit will be filed in Miami against Costa and its parent company, Carnival Corp., the Italian consumer group Codacons said Saturday. The suit, in collaboration with two U.S. law firms, is "aimed specifically at getting compensation for all damages to the boat passengers," Codacons said in a statement. The class-action suit is open to passengers of any nationality, it said.