Bangladeshi officials say floods have killed at least 35 people and left more than four-and-one-half million stranded or displaced.
They say floods are affecting more than half the country. Hundreds of thousands of people have packed into 600 relief centers or sought higher ground.
In India, officials say at least 22 people were killed on Wednesday when an overcrowded boat sank in a rain-swollen river in the north of the country.
They say at least four people are still missing. At least 45 people were rescued when the boat went down in Maharajganj district of Uttar Pradesh.
Monsoon rains have caused flooding in the area that has affected thousands of people.