"Modi called up Kumaraswamy and assured him of all help in rescue and relief operations in flood-hit Kodagu district," said the statement from the Chief Minister's camp office at Madikeri, about 270 km from Bengaluru.

Kumaraswamy, who has been camping in the district since Saturday to supervise the operations, briefed Modi on the flood situation in the rain-hit district and how the Army, Navy and National Disaster Response Force were coordinating the efforts.

Modi earlier tweeted that he spoke to Kumaraswamy from New Delhi on the flood situation in the affected district.

"Extended all possible support in the rescue and relief operations. I pray for the safety and well-being of those in the flood affected areas," the Prime Minister said in a tweet.

Kumaraswamy also briefed President Ram Nath Kovind on the rescue work in the district when the latter called on him from New Delhi earlier in the day.

"The Chief Minister informed the President that the Indian Army, Navy and other state and central agencies have rescued over 3,500 people so far," the statement noted.

Around 4,225 marooned people were rescued till Sunday evening from towns and villages across the district despite incessant rains hampering the operation.

Of the rescued, 3,601 are staying in 36 relief shelters in the district and efforts were on to reach others stranded on hilltops.

Located in the southern Western Ghats mountain range, the coffee-growing district is the worst-hit by the monsoon rains since June's first week.

The incessant rains have caused flooding and landslips across the region, damaging the arterial roads.