Heavy rains on Sunday night and Monday morning have flooded new areas in Assam.

Official reports said a heavy downpour in the hills of Arunachal Pradesh and catchment areas of the Brahmaputra has led to flooding in large areas in Upper Assam. So far, only Lower Assam had been affected by the floods.

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The toll is now up to 77 and at least three districts of Upper Assam -- Tinsukia, Dibrugarh and Dhemaji -- have been affected. Fresh reports of drownings have been received from Dhubri and Morigaon.

At least five children in Birsing Char area in South Salmara division of Dhubri district died of water-borne diseases.
 
Army has been called out for rescue and relief work in Tinsukia district, where at least 50 villages have been flooded.

With the recovery of the carcass of a seven-month rhino at the Bontapu forest in the Orang National Park, the number of wild animals killed in the floods has risen to 231.

The rivers Dhansiri and Pachnoi besides the Brahmaputra, have submerged almost 90 per cent of the park area.

The situation, meanwhile, continues to worsen in Lower Assam.

Prime Minister Manmohan Singh will visit the state on Tuesday to take stock of the situation.