* Many missing after fire near Athens kills at least 83
* Rescuers, volunteers continue door-to-door search
* Relatives desperate, survivors angry
* Town planning 'chaos' didn't help, says minister
* Flash flood hits part of Athens (Adds minister's comment, detail)
By Renee Maltezou and Alkis Konstantinidis
MATI, Greece July 26 (Reuters) - Grief became tinged with anger in Greece on Thursday as rescuers searched scorched land and the coastline for survivors, three days after a wildfire destroyed a small town outside Athens and killed at least 83 people.
In a nation numbed by the scale of devastation, desperate relatives appeared on television to plead for information on those missing, while questions mounted why so many were trapped by a wall of flame in streets with no exit route at Mati.
"This shouldn't have happened, people perished for no reason," a tearful woman shouted at Defence Minister Panos Kammenos as he visited the town and nearby fire-ravaged areas. "You left us at God's mercy!"
It was unclear why there was no evacuation order, with the fire brigade, local administration and central government each saying the other was responsible.
With the toll from Greece's deadliest wildfire in decades expected to rise further, about 300 firemen and volunteers combed the area for dozens still missing.
One woman was looking for her brother, who had been returning from work when the flames took hold. "My father was the last person to talk to him on Monday evening," Katerina Hamilothori told Skai TV. "We have had no news at all."
The cause of the fire is still unclear, but authorities, including an Athens prosecutor, were investigating how it started simultaneously from three different locations and the way it was handled.
Haphazard and unlicenced building - a known feature of many areas across Greece - was also blamed. Many routes to the beach were walled off.
"How is it possible to have so many lives lost and not investigate who is responsible for such town planning chaos?" said Infrastructure Minister Christos Spirtzis.
Adding to the misery, an area Athens was hit by flash floods on Thursday, damaging scores of cars.
IDENTIFYING THE DEAD
Outside the coroner's service in Athens, the mood was grim as relatives of victims arrived to submit information and blood samples which could assist identifications.
"This is a difficult process, more difficult than other mass disasters we have dealt with," said coroner Nikolaos Kalogrias, adding that the bodies of most of the victims were completely charred.
About 500 homes were destroyed, and the fire brigade said there were closed-up homes that had not yet been checked.
The left-led government announced a long list of relief measures including a one-off 10,000 euro payment and a job in the public sector for victims' spouses and near relatives. But for many, that was not enough to ease the pain.
"A drop in the ocean," read the front page of newspaper Ta Nea.
The fire broke out on Monday at 4:57 p.m. and spread rapidly through Mati, which lies fewer than 30 km (17 miles) east of Athens and was popular with local tourists.
Firefighters described a rapid change in the direction of the wind, which also picked up speed, and some suggested the thick covering of pine trees and a mood of panic was a deadly combination that would have been hard to combat. (Additional reporting by Karolina Tagaris and Angeliki Koutantou; writing by Michele Kambas; Editing by John Stonestreet and David Evans)
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