Indian authorities are trying to rescue thousands of people stranded in flooded villages after a week of heavy rains killed at least 52 people and uprooted tens of thousands of others from their homes in Bihar state in the east and Assam in the northeast.

A government statement says 26 deaths have been reported in Assam, where incessant downpours have damaged roads and snapped telephone cables in several districts.

Home Minister Rajnath Singh flew over the worst-hit areas on Saturday and said the floods were "very serious."

Twenty-six deaths have been reported in eastern Bihar due to drowning and home collapses in 10 districts bordering Nepal.

Floods are an annual occurrence in Assam, Bihar and many parts of India during the June-September monsoon season.