Three people were killed in central Switzerland after they were caught in flash floods overnight caused by heavy thunderstorms, police said Saturday.

A couple died in the small town of Huttwil after they were swept away by a small river which turned into a raging torrent during the storms late Friday, police in the canton of Bern said at a press conference.

Their son was saved by onlookers, they added.

Police also said an elderly woman died in the nearby village of Eriswil when her home was flooded.

Cars were swept away by the fast flowing water, several houses were flooded and two bridges in the region were severely damaged, authorities said.

Local roads were also cut briefly as flood waters reportedly rose within seconds.

Flash flooding and mudslides were also reported overnight during storms near Lucerne in central Switzerland and in the northern city of Basel, mainly affecting home cellars and roads. No one was injured, authorities said.