"This is tough stuff out there," said Robert Francis, vice-chairman of the National Transportation Safety Board (NTSB), which has taken over the rescue operation.
The police divers were joined yesterday by US Navy underwater experts with "pinger" sonar equipment they hoped would locate signals from the plane's flight recorders.
After cutting through razor-sharp, 8ft sawgrass on so- called airboats - fan-propelled platforms driven by "swamp rats" who usually fish the swamps or ferry tourists - the rescuers found the aircraft's engines and parts of its pale blue tailplane on Sunday evening.
But there appeared to be little else. Mr Francis said it was the most difficult rescue his experts had ever faced. Some rescuers said yesterday they had touched - poking with poles - a large, sunken piece of debris which could be part of the fuselage. But the problem was how to get it out of sinking swamps 300 yards from the nearest levee, or causeway, and reachable only by the grass-cutting airboats.
Rescuers began talking of weeks, rather than days.
US Navy underwater experts arrived yesterday to probe the murky water, where divers said they could not even see their hands in front of them. The divers also expressed fears that deadly 12ft alligators which inhabit the area, but would have fled the spilt fuel on Saturday, may return, attracted by the bodies.
It was an eerie, surreal sight, with the whirl of helicopter blades, the boatfans, the chatter of confused birds and the buzz of local "deerflies" and mosquitoes sporadically interrupting otherwise total silence. The swamp seemed to have literally swallowed up the entire aircraft into its sawgrass cover, 20ft layer of mud, soggy peat and limestone base.
Only a slightly darker shading, perhaps from aviation fuel but looking as though the site was under a small cloud, gave a hint as to where the jet sank. By yesterday, the area looked like a flooded golf course as rescuers planted orange flags to mark the path of their probe.
Some rescue workers were seen carrying a few military-style body bags from the swamp to coroners' vans on a nearby sand-and-stone levee. The bags were clearly not empty but nor did they appear to weigh enough to carry entire bodies. Local officials looking on from a distance said the bags may have contained body parts, personal effects or "sensitive debris," which may be able to cast light on Saturday's crash of the ValuJet airline DC-9. It went down eight minutes after taking off from Miami International Airport to Atlanta, Georgia, as the 35-year-old woman pilot, Candalyn Kubeck, attempted to return to the airport because of black smoke in the aircraft.
The British vice-consul in Orlando, Florida, Linda Nassar, said she was trying to confirm reports of up to three Britons on board, named as Roger and Devlin Loughney and James Allaway, the latter believed to have been a Miami resident.
The first two may have been wrongly listed as Britons because they had arrived from the UK before buying "walk-up" tickets to Atlanta, she said. ValuJet said it had contacted all next-of-kin but the British vice-consul said the airline had not yet passed on details.