At least 40 people, including women and children, were feared drowned when a vehicle carrying them was washed away by the swollen Narukulapadu stream along the Guntur-Amaravathi road on Sunday morning, police said.
"Ten people were rescued by the villagers. It was difficult to guess how many people were travelling in the ill-fated truck," they said.
Police said traffic on the busy Guntur-Amaravathi road came to a halt on Sunday morning as the water from the flooded stream started overflowing.
Several state-owned buses were stranded on both sides of the swollen stream. A truck driver offered to ferry the passengers across the stream and about fifty people boarded the vehicle.
As the truck was midstream, the water swept it away, police added.
Under the influence of depression in the Bay of Bengal, Guntur district has been experiencing torrential rains for the last three days, triggering floods.