Troops were put on alert on Friday as the first wave of flash floods triggered by heavy monsoon rains hit Assam, officials said.
"We have put civil officials and security personnel in the state on maximum alert with flood waters overtopping a national highway in eastern Assam, besides entering some low lying areas," Assam Flood Control Minister Nurzamal Sarkar told AFP.
"We are yet to get official reports if floodwaters have already entered villages in Dhemaji district. Unconfirmed reports say up to 100 villages were submerged."
Floodwaters of the Jiadhol River, a tributary of the mighty Brahmaputra River, had breached an embankment in the eastern district of Dhemaji on Thursday night.
"Road and rail links between Dhemaji and the rest of Assam remain cut off," Dhemaji district police chief N.M. Haque said by telephone.
A Central Water Commission bulletin said the Brahmaputra was showing a rising trend all along its course with the river flowing above the danger level in one channel.
"The water level of the Brahmaputra is expected to rise in the next 48-hours," the bulletin said.
During the high floods caused by the surging grey waters of the Brahmaputra, some four million people were rendered homeless in Assam last year.
"We have reconstructed several breached embankments spending about 60 million rupees and hope this time the floods would not leave a trail of destruction as it does in Assam every year," the minister said.
"But then you never know how the river current behaves as it is very unpredictable."
Floods in Assam normally begin by end of May and continue for about two months causing widespread devastation to agriculture, human lives, and personal effects.
The Regional Meteorological Centre here in Guwahati has forecast more rains in the next two days.
"Rain accompanied by thundershowers could occur in most parts of Assam and adjoining northeastern states in the next 48-hours," a weather bulletin Friday said.
Meanwhile, officials say people in flood-prone areas have started stockpiling essentials.
"People don't have that much resource to stockpile sufficient foodstuffs but then whatever little they could, they are saving for survival during the floods," a magistrate in Dhemaji said.