A severe snowstorm disrupted road and air traffic in the Greek capital of Athens and in nearby Istanbul, Turkey, while snow blanketed most of the two countries, including several Aegean islands.

The Greek government declared a holiday on Tuesday in the greater Athens area, parts of central Greece and the islands to keep people at home.

“We ask citizens to avoid leaving their homes. It will be a difficult night,” Climate Change and Civil Protection Minister Christos Stylianides said. “The height of the snow is unprecedented in some areas.”

Turkish authorities in Istanbul, a metropolis of 16 million people, suspended intercity bus service and temporarily blocked travel to the city from Turkey’s Thrace region.

People stranded on roads abandoned their vehicles to walk home or crowded subway and other public transportation.

Schools across Turkey are closed for a winter break, but universities halted classes for two days. Public offices and shopping malls closed early.

“It is a difficult night,” Istanbul Mayor Ekrem Imamoglu declared. He urged people not to leave their homes. Snow had reached 80-85 centimetres (31-33 inches) deep in some parts of Istanbul, he said.

Flights in and out of Istanbul Airport were suspended until 4am (01:00 GMT) on Tuesday.

Authorities worked to clear runways and a road leading to the airport, where the roof of a facility used by Turkish Airlines’ cargo department collapsed from the weight of snow. No one was hurt.

In Greece, schools in many areas were closed. Government spokesman Giannis Oikonomou said more than 46,000 school classes were being held online.