Flash floods and landslides triggered by heavy monsoon rains in India's northeast have left at least 10,000 people displaced in Assam and Arunachal Pradesh, officials said Thursday.

The two states, bordering China's Tibet region, have been hit by the first wave of flooding.

In Assam, floodwaters of the Brahmaputra river have inundated at least 35 villages in the eastern districts of Dhemaji, Tinsukia and Dibrugarh.

"Some 8,000 people are now taking shelter in raised platforms or in government buildings," an Assam government official said.

According to a Central Water Commission bulletin Thursday, the Brahmaputra was flowing above the danger mark in at least six places with the river maintaining a rising trend.

A government flood control department official said the eastern district of Dhemaji, 550 km from Assam's main city of Guwahati, has been cut off since Tuesday with floodwaters breaching a main highway.

The Brahmaputra was also threatening to spill its banks along Majuli, the world's largest river island, 350 km from here.

Every year floods leave a trail of destruction, washing away villages, submerging paddy fields, drowning livestock, besides causing loss of human life and property, in the state of 26 million.

Last year, at least 200 people died and more than 12 million displaced in the floods.

In adjoining Arunachal Pradesh, floodwaters of the river Lohit have led to disruption of road communications and triggered heavy landslides.

"The districts of Lohit and Anjaw have remained cut off from the rest of the state with the main roads inundated by floodwaters," said a government official from the state capital Itanagar.

He estimated that least 2,000 people were left homeless in the two districts due to flooding.

The 2,906 km long Brahmaputra is one of Asia's largest rivers that traverses its first stretch of 1,625 km in China's Tibet region, the next 918 km in India and the remaining 363 km through neighbouring Bangladesh before converging into the Bay of Bengal.