Rescuers were concentrating their efforts on locating the bodies of the two remaining victims in the burned out wreckage of the aircraft at the bottom of a ravine. The search for bodies from Sunday's crash had gone on throughout the night under powerful arc lights.

The interior ministry said identifiable bodies would be taken to an establishment at Goudi, near Athens city centre, where relatives could begin identifying them.

Remains which were not identifiable would be DNA tested at the morgue in the port of Pireus, where all the bodies had been taken initially, Interior Minister Prokopiis Pavlopoulos said after a meeting during the night with Cypriot officials.

Relatives of the victims were expected to arrive in Greece early Monday on a specially-chartered flight.

Second black box found

The head of the investigation into the crash, Akrivos Tsolakis, confirmed the discovery of the plane's second "black box," containing recordings of the pilots' cockpit conversations, but said it was in a "very bad state."

"We don't know if we will be able to get something from it," he said.

That and the other black box, the flight data recorder, would be sent to Paris for analysis, under agreement between France and Greece, Tsolakis said.

Children on board

The Helios Airways Boeing 737 was about to land at Athens airport for a stopover on its journey from Larnaca in Cyprus to the Czech capital Prague when it crashed at Varnava, a largely uninhabited area 40 kilometers (25 miles) northeast of Athens.

Helios said most of the passengers on the airliner were Greek Cypriots. Of those aboard, 59 adults and eight children were heading to Athens; 48 were continuing on to Prague.

A Cypriot official said that the first indications of the Greek authorities were that the crash was not the result of a terrorist attack.

Causes unknown

The cause remains as yet unknown, although there have been harrowing accounts of an apparent crisis in the cockpit in the plane's last minutes with Greek officials saying one of the pilots was slumped in his seat. Pilots of two F16 fighters sent up to escort the airliner before the crash "saw a situation that was not normal in the pilots' cabin."

One of the F-16 pilots reported that he could not see the captain in the cockpit and his co-pilot appeared to be slumped in his seat, a Defence Ministry official told reporters.

Greek police suspect the cause was a sudden drop in the cabin pressure, a senior official at the Greek public order ministry said. The pilots of the plane, one of whom was German, had mentioned a problem with the aircraft's systems when he spoke to the Athens control tower before contact was lost, said the official.

"The pilot has turned blue," one passenger said in a mobile text message to his cousin. "Cousin farewell, we're freezing."

But in Paris, accident investigator Francois Grangier told AFP that a sudden loss of pressurization would not have caused the plane to crash, nor would it have made the pilots immediately lose consciousness.

The plane would have been at fairly low altitude as it approached Athens airport, and Grangier said loss of pressurization would not have had any effect on the aircraft's structure. He also said the pilots would have had their own oxygen supply.

Another expert said that in the case of sudden depressurization because of structural damage, for example the blowing out of a window, the internal temperature would plummet and the plane would crash.

"All planes have problems"

Helios, established in 1999, is the first private airline in Cyprus. It had a fleet of four Boeing 737 jets and operated flights to London, Athens, Sofia, Dublin and Strasbourg in France, among other places.

The crash was the worst airline disaster in Greek history since a 1974 terrorist bomb aboard a TWA Boeing 707 caused it to crash in the Ionian sea with the loss of 88 lives.

"All planes have problems from time to time without exception," said Helios managing director Demetrios Pantazis. Helios rejected any suggestion that the aircraft was less than airworthy, saying it had undergone a complete technical check before departure.

Greece has declared a day of mourning for Tuesday, when flags will fly at half-mast and a three-minute silence will be observed in public buildings. Cyprus will observe three days of mourning.