Officials have described the floods as a 'catastrophe'
At least 40 people have died and over a million have been affected by floods in three districts of the northern Indian state of Bihar, officials say.
The banks of the Kosi river overflowed days after the part of the river in neighbouring Nepal breached an embankment there.
The affected region is not flood-prone and the area last saw floods in 1952.
Officials have described the situation as "alarming" and a massive relief and rescue operation has been launched.
Rescue and relief
Supaul, Araria and Madhepura districts bordering Nepal are the worst affected.
Over 200 rowing boats and 25 motorised ones have been pressed into service to rescue stranded people, and reach relief supplies.
Indian air force helicopters are dropping food packets in the area and over 50 relief camps have been opened in the affected districts, officials said.
People in the area have taken refuge on embankments, highways, and buildings to escape the flood waters.
"Around 700-800 houses have been damaged, people are somehow managing to live on wooden logs and rooftops. Many rooftops are also damaged, those people don't know where to go," a flood victim in Madhepura, Sanjeev Kumar, was quoted by news agency Reuters as saying.
On Tuesday morning, about 100 prisoners were shifted from two jails in Madhepura and Birpur (in Supaul) to other prisons in the state.
According to reports, crops on tens of thousands of hectares of land have been damaged by the floods.
Bihar Chief Minister Nitish Kumar has described the floods as a "catastrophe".
The state government has issued an appeal to relief agencies to step in and help get relief to the flood-affected.
However, many affected people say they have not received any government help.
"No arrangements have been made, we live here only, near the river, we drink its water when we feel thirsty even though people die because of this river," Reuters quoted a villager, Jugat Lal Yadav, as saying.
Meanwhile, in the neighbouring Uttar Pradesh state, more than 700 people have died as a result of heavy rains and monsoon floods since June.
Officials said most deaths were caused by house collapses in villages.