Tornadoes and violent hailstorms killed six tourists in northern Greece late Wednesday, the police said.

Dozens more were injured when strong winds hit the region of Halkidiki, near the city of Thessaloniki, authorities added.

“Six tourists were killed and at least 30 people were injured during this cyclone,” Charalambos Steriadis, head of civil protection in northern Greece, said.The freak storm only lasted about 20 minutes, according to witnesses interviewed by state television ERT.

A Czech couple died when strong winds blew their caravan away while a Russian man and his son were killed by a falling tree, police said.

“It was an unprecedented phenomenon,” very strong winds, tornadoes and violent hailstorms, Steriadis said, adding that Halkidiki had declared a state of emergency.At least 140 rescue workers were involved in the operation, emergency chief Vassilis Varthakoyannis said.