"The flood situation in northern Bangladesh has been aggravated overnight. Water levels of both the Ganges and the Brahmaputra have increased, inundating vast new areas," Dhiraj Malakar, the country's disaster management secretary, said.
Worse to come
Thousands of military, government and volunteer groups have been evacuating people and distributing food and medical aid.
The government's flood forecasting and warning centre has said that the situation could worsen as the two major Himalayan-fed rivers have continued to swell and were set to flood the country’s central regions within two days.
Last month, landslides triggered by heavy rains killed at least 126 people in the southeastern city of Chittagong on the Bay of Bengal.
Bangladesh is surrounded by a network of 230 rivers and has annual floods with at least a fifth of the country submerged each year.
The monsoon season has also hit Nepal hard with the heavy rains leaving 20 people dead and 50,000 families displaced.