Torrential rains unleashed flash floods and triggered landslides on Indonesia’s Sumatra island, killing at least 10 people and leaving six others missing, police said Wednesday.

Rescue teams were struggling to reach affected areas in six regencies of North Sumatra province after the monsoon rains over the past week caused rivers to burst their banks.

Rescue workers by Wednesday had recovered at least five bodies and three injured people in the worst-hit city of Sibolga and were searching for four villagers who were reported missing, police said in a statement.

Sibolga's police chief said emergency shelters have been set up and authorities urged residents in high-risk zones to evacuate immediately, warning that continued rainfall could trigger more landslides after six landslides in the hilly city flattened 17 houses and a café.

Heavy seasonal rain from about October to March frequently causes flooding and landslides in Indonesia, an archipelago of 17,000 islands where millions of people live in mountainous areas or near fertile floodplains.