A forensic expert has told Sky News it may take many months to formally identity the victims of the Malaysia Airlines plane attack.
Peter Vanezis, a professor of forensic medical sciences, said facial recognition could not be relied upon due to the conditions in which the bodies had been left.
Instead, teeth, which last a long time in poor conditions and are also resistant to heat, may prove vital.
Prof Vanezis was speaking as the bodies of some of the first victims recovered from the crash site in eastern Ukraine arrived in the Netherlands.
It is thought the remains of more than 80 of the 298 people killed in the disaster still remain at the scene.
There has been condemnation over the lack of dignity and respect with which the dead have been treated, with human remains left strewn across fields in the searing summer heat.
There has been criticism over the lack of dignity afforded the dead This would add to the problems of identifying the bodies, according to Prof Vanezis.
"It can be extremely difficult," he said.
"Identification, even in the best circumstances, can take a number of months and it has to start once the bodies are actually found.
"Obviously, once the bodies are taken back to the mortuary and the doctors can do their investigations, they will have with them all the information about the deceased before they died to compare with what they find on the deceased.
"For example, they will be able to look at dental records, DNA tests and in some cases fingerprints or other medical implants that are present on the bodies.
"They will also need to look at any documentation or clothing that will help with identification.
Bodies of some of the first victims have now been flown to the Netherlands "But of course if this isn't done properly from the beginning and things aren't collected in the correct manner, this makes the task very difficult indeed."
On the importance of dental records, Prof Vanezis said: "You cannot rely on facial identification.
"It's unreliable in these circumstances with the conditions in which the bodies are in.
"We know the teeth last a very long time in very poor conditions and also are very resistant to heat as well.
"They make an ideal method for identification in these circumstances.
"But of course one uses a number of other methods as well to confirm identity. You wouldn't just rely on one particular method."
The bodies cannot be returned to relatives for burial or cremation until each body has been identified correctly.
"The worst thing would be to give the wrong person to the wrong family," Prof Vanezis added.
"It's certainly a challenging task."
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