* Three days mourning declared over “unspeakable tragedy”
* Boats rescue hundreds from beaches, others trapped
* Greece’s worst wildfire since 2007 still smouldering
* European Union states respond to Greek appeal for help (Updates with fire contained, prosecutor investigation)
By Vassilis Triandafyllou and Alkis Konstantinidis
MATI, Greece, July 24 (Reuters) - Wildfires sweeping through a Greek resort town have killed at least 74 people including families with children found clasped in a last embrace as they tried to flee the flames.
The inferno was Greece’s deadliest since fires devastated the southern Peloponnese peninsula in August 2007, killing dozens. Officials said it broke out in the town of Mati, 29 km (18 miles) east of Athens, late on Monday afternoon and was contained by Tuesday afternoon but the risk remained of it reigniting in scrubland parched by Greece’s searing summer heat.
“Greece is going through an unspeakable tragedy,” Prime Minister Alexis Tsipras said as he appeared on television to declare three days of national mourning.
Emergency crews found the bodies of 26 victims, some of them youngsters, lying close together near the top of a cliff overlooking a beach. They had ended up there after apparently searching for an escape route.
“Instinctively, seeing the end nearing, they embraced,” the head of Greece’s Red Cross, Nikos Economopoulos, told Skai TV.
Many hours after the blaze broke out, the strong smell of charred buildings and trees lingered in the air in parts of Mati on Tuesday. White smoke rose from smouldering fires.
Residents, their faces blackened by smoke, wandered the streets, some searching for their burned-out cars, others for their pets. The eerie silence was punctured by fire-fighting helicopters and the chatter of rescue crews.
A Reuters photographer saw at least four dead people on a narrow road clogged with cars heading to a beach.
Many in the area were unable to escape the fast pace of the blaze even though they were a few metres from the Aegean Sea or in their homes, the fire service said.
“We went into the sea because the flames were chasing us all the way to the water. It burned our backs and we dove into the water,” said Kostas Laganos, a middle-aged survivor.
He compared the ordeal to the destruction of the city of Pompeii, where thousands were incinerated by the volcano of Mount Vesuvius in 79 AD: “I said my God, we must run to save ourselves and nothing else.”
Working through the night, coastguard vessels and other boats rescued almost 700 people who had managed to get to the shoreline and pulled another 19 survivors and six dead bodies from the sea, the coastguard said.
In total, at least 74 people had been killed, a fire brigade spokeswoman said, and the death toll was expected to rise. Poland said two of its citizens, a mother and her son, were among the victims.
It was not clear how many people remained unaccounted for as boats combed beaches for any remaining survivors, with military hospitals on full alert, the Greek government spokesman said.
One of the youngest victims was believed to be a six-month-old baby who died of smoke inhalation, officials said. At least 187 people were injured, among those 23 children.
Wildfires are not uncommon in Greece, and a relatively dry winter and hot summer helped create the current tinder-box conditions. The cause of the current blaze was not immediately clear and an Athens prosecutor ordered an investigation into it.
Mati, 29 km (18 miles) east of Athens, is a popular spot for Greek holiday-makers, particularly pensioners and children at summer camps.
Greece’s fire service said the intensity and spread of the wildfire at Mati had slowed as winds died down on Tuesday afternoon, but it was still not fully under control.
It urged residents to report missing relatives and friends. Some took to Twitter and Facebook, posting photographs of young children and elderly couples they hoped to track down.
Greece issued an urgent appeal for help to tackle fires that raged out of control in several places across the country, destroying homes and disrupting major transport links.
Newspapers printed banner headlines including “Killer Fire” and “Hell”.
Cyprus, Spain, Italy, Croatia and Portugal offered assistance after Greece said it needed air and land assets from European Union partners.
“Our thoughts go to Greece and the victims of the terrible fires,” French President Emmanuel Macron said in tweets published in French and Greek.
Pope Francis said in a telegram he was deeply saddened by the tragedy and prayed for the victims and their families.
Additional reporting by Angeliki Koutantou, Michele Kambas, George Georgiopoulos, Renee Maltezou, Karolina Tagaris, Costas Baltas, Deborah Kyvrikosaios in ATHENS, Philip Pullella in ROME, Agnieszka Barteczko in WARSAW, Andrei Khalip in LISBON Writing by Karolina Tagaris Editing by Mark Heinrich