Greece was in mourning Thursday as rescue crews tried to locate several people missing in a flood that killed 15 people near the capital, as rain continued to fall.
Authorities said at least five people were still missing in Mandra, one of three towns about 50 kilometres (30 miles) west of Athens hit by a freak flood early on Wednesday.
Prime Minister Alexis Tsipras, who has declared three days of national mourning after the disaster, was touring the area Thursday.
"It was like a tsunami," Evangelos Kolovetzos, a local shopowner, told AFP.
"The water in my house rose to 3.5 metres (11.5 feet)," said Sotiris Loukopoulos, whose pharmacy is the only one still open in Mandra.
"Five pharmacies were destroyed, we are still operating because we are on higher ground," he told Athens municipal radio, as residents tried to clean their yards with shovels and hoses.
Over a hundred firefighters aided by army machinery were mounting search and rescue efforts in Mandra, Nea Peramos and Megara, the semi-rural areas west of Athens hit hardest by the deluge.
The operation unfolded alongside gutted, debris-strewn streets, overturned cars and hundreds of flooded homes and shops as state utility crews laboured to restore power and water services.
Emergency crews used pumps to drain water as police reinforcements were sent to the area to prevent looting.
The poor weather is set to continue until the weekend, raising concerns for hundreds of people with waterlogged homes.
"We are trying to deal with two torrents, one of which is still flowing through the centre of Mandra," a civil protection agency source told AFP.
Meteorologists said Wednesday's heavy rainfall was concentrated on a nearby mountain that had been devastated by wildfires in 2016, facilitating the ensuing mudslide.
Neighbouring areas saw much less rain, they said.
Twelve people are hospitalised, one in serious condition.
"At this time, declaring a state of national mourning over this great tragedy is the least we can do," Tsipras said in a televised address on Wednesday.
"I pledge that we will stand next to the families of the victims with all the means at our disposal," he said.
As a first step, the state will cover the funeral expenses, the interior ministry said.
Food, water and blankets have been rushed to the area, hit by what locals have described as the worst flooding in 20 years.
"The situation is unprecedented," said Constantinos Palaioroutis, director of the hospital nearest to the area.
"We have never dealt with such a situation, so many victims in such a short space of time," he said.
Some elderly people died inside their homes while others were trapped in their cars as they drove to work.
Parts of the area are without water and electricity for a second day, and much of the damage will take days to repair, though fortunately the sewage system is still functioning, the state water company said.
A 364-cabin cruise ship has been commissioned to shelter some of the homeless, should they request it, the merchant marine ministry said.
Once a rural area, Mandra and neighbouring towns were rapidly transformed into a logistics hub for factories and warehouses over the last 20 years, covering riverbeds that would have provided natural drainage.
Experts have said ill-conceived construction in the area—some of it by local municipal authorities—meant this was a disaster waiting to happen.
Corrective drainage works for the area were approved in 2016 but work has yet to begin.
A prosecutor has ordered an investigation into building violations in the area, where two people had already died in flooding that struck in 1996.
"There is a bad precedent with public works in this country," Interior Minister Panos Skourletis told Antenna TV.
Government spokesman Dimitris Tzanakopoulos said "Illegal building was a response to huge social and economic inequality."
"These were poor people, for years the state allowed them to operate in a specific way," Tzanakopoulos told state TV ERT.
Stricken areas will request EU solidarity funds, the Athens governor's office said.
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