A rare waterspout caused by a tornado has struck the German port city of Kiel, throwing people from boats and damaging property.

Several rowers out in the water were injured as winds of over 100km/h lashed the northern coast, police said. Four people were seriously hurt in Kiel's dockside area.

The roofs of some buildings were torn off and trees were uprooted.

Waterspouts occur when a tornado forms over oceans, rivers or lakes.

They usually disperse after a few minutes, but they can pose serious danger to boats that get close.

In Kiel, on Germany's Baltic Sea coast, members of a rowing club were thrown into the water and people jumped into the water to pull them to shore.

Images posted on social media showed the waterspout looming over the German city./bbc