Secretary-General Antonio Guterres has offered United Nations (UN) assistance to India and other flood-affected countries in the region.
"The UN stands ready to work with the authorities in the affected countries as they respond to the humanitarian needs resulting from this ongoing monsoon season," his deputy spokesman Farhan Haq said on Monday.
Mr Guterres "is saddened by the loss of life, displacement of people and destruction of property due to the heavy monsoonal rains and associated flooding across South and South-East Asia, most notably in India, Bangladesh, Nepal and Myanmar", Mr Haq said.
"He extends his condolences and solidarity to the families of the victims, to the governments and people of the affected countries and wishes those injured a speedy recovery," he added.
Flash floods caused by heavy rains in catchment areas of Nepal have ravaged a dozen districts of Bihar so far, claiming 78 lives and affecting 55 lakh people, the state's disaster management department said on Thursday.
A tiger escaped from the Kaziranga National Park in flood-ravaged Assam and stretched out on a shophouse bed Thursday, startling residents and shining a spotlight on the plight of animals caught up in the deluge.
Chest-deep in brown, flowing monsoon water and holding bags of clothes and utensils above their heads, residents in Bihar are hungry and in despair.
A 24-year-old woman in flood-hit Assam gave birth to a baby boy in a boat on Monday and named him Krishnaafter the Hindu Godwhowas also believed to have been born during massive floods.