A wildfire that swept through a small resort town near Athens, in eastern Greece has claimed at least 74 lives, officials confirmed.
More than 172 people have been injured, including 16 children, with 11 adults in a serious condition, the government said.
Greek prime minister Alexis Tsipras declared a three-day national mourning period.
“Greece is going through an unspeakable tragedy,” he said in a televised appearance.
The number of casualties could rise further as more gutted homes and cars were checked, the emergency services warned.
Early on Tuesday morning the Red Cross said that 26 bodies had been found together outside a villa in Mati. Fire officials later confirmed the overall death toll had risen further.
“Unfortunately we found 26 charred bodies, between two homes,” Nikos Economopoulos, president of the Greek Red Cross, told Greek state tv.
The group of 26 victims, some of them youngsters, lying close together near the top of a cliff overlooking a beach.
They had apparently hugged each other as they died, Economopoulos said.
“They had tried to find an escape route but unfortunately these people and their kids didn’t make it in time. Instinctively, seeing the end nearing, they embraced,” he said.
Coastguard vessels and other boats rescued almost 700 people who had managed to get to the shoreline and plucked another 19 survivors and four dead bodies from the sea where they had fled to save themselves, the coastguard said.
Ambulance Service deputy director Miltiadis Mylonas said the death toll is likely to rise.
“It took people by surprise and the events happened very fast,” he said.
The fire in the seaside village Mati, some 29 km (18 miles) east of Athens, was by far the country’s worst since flames devastated the southern Peloponnese peninsula in August 2007, killing dozens.
Monday’s late afternoon fire was one of several that broke out in the country amid a sweltering heat wave.
“Mati doesn’t even exist as a settlement anymore,” one woman told Greece’s Skai TV. “I saw corpses, burned-out cars. I feel lucky to be alive.”
Mati is in the Rafina region which is a popular retreat with local tourists, particularly pensioners and children at holiday camps.
It is not yet clear whether any British tourists were caught up in the fire.
A Foreign and Commonwealth Office spokesperson said: “Our thoughts are with all those affected by the wildfires in Greece.
“We are in contact with the Greek emergency services responding to the fires, and will do all we can to assist any British people who require our help.”
Government spokesman Dimitris Tzanakopoulos said in a televised statement that more than 88 adults and 16 children were injured.
The coastguard later said the bodies of four more people were retrieved from the sea.
One of the youngest victims was thought to be a six-month-old baby who died of smoke inhalation.
A witness told Reuters they had seen at least four dead on a narrow road clogged with cars heading to the safe haven of a nearby beach.
Hundreds of people had scrambled to the sea as the blaze closed in close to the shore. They were picked up by passing boats.
Some parts of Mati were still smouldering white smoke early on Tuesday. Burned-out cars were scattered outside gated compounds where three- and four-storey buildings bore signs of fire damage.
“We are dealing with something completely asymmetric,” Greek Prime Minister Alexis Tsipras, looking pale, said after cutting short a visit to Bosnia.
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.
Cyprus and Spain offered assistance after Greece said it needed air and land assets from European Union partners.
With additional reporting from George Bowden.