At least six people have been killed and more than 100 others injured after gale-force winds, rain and hailstorms lashed northern Greece late Wednesday.
Authorities said the victims included two Czech nationals, two Romanians and two Russians.
Television footage showed strong winds uprooting trees and collapsing roofs in the Halkidiki peninsula.
According to reports, some suffered head injuries from falling trees and other objects.
Prime Minister Kyriakos Mitsotakis is reportedly monitoring the situation while emergency services are being carried out.
Meteorologist Klearxos Marousakis described such severe weather conditions unusual for summers, which are typically hot and dry.

Russian drone, missile attack on Kyiv hits residential buildings
US, Iran talks conclude in Doha, focused on Strait of Hormuz
Trump honours Theodore Roosevelt in North Dakota, debuts new Air Force One
Kenyan court charges 8 schoolgirls with fellow students' murder
At least 5 people killed in fire in Antwerp apartment block