Two victims were crushed to death when a large rock smashed their house in the Black Sea port city of Trabzon, local governor Recep Kizilcik told Anatolia.

The third perished when a landslide unleashed by heavy rains destroyed a house in a village in the neighbouring province of Giresun, the agency said, adding that rescuers were looking for another person in the debris.

Killer landslides are frequent on Turkey's mountainous Black Sea coast, where mushy ground typical of the region is easily unsettled by torrential rains and many people live in traditional wooden houses perched on hillsides.

Also on Saturday, a rescue operation involving a helicopter was launched for 18 people stranded in a bus on a mountain road in Rize province in the same region amid blizzards and avalanches, officials said.