Officials said none of the passengers have been found and the bus had not been pulled out of water.
At least four passengers were killed and over a dozen others are feared dead when a bus fell into a roadside pond in Bihar's Madhubani district today.
The accident took place at Basaitha chowk under Bennipatti police station in Madhubani, about 50 km from the district headquarters.
Deputy Superintendent of Police (DSP) Benipatti Nirmala Kumari said four bodies have been fished out so far and search is on for others.
About 65 passengers were on board the bus. Some of them swam to safety while over a dozen are feared to have been killed.
The private bus was on way to Sitamarhi from Madhubani when the mishap took place on the state highway.
Meanwhile, in Patna, Chief Minister Nitish Kumar expressed deep sorrow over death of passengers in the bus mishap at Madhubani.
The chief minister said in a statement that the reason of the accident was being looked into. He instructed officials to speed up relief and rescue operation.
Mr Kumar instructed Revenue minister Madan Mohan Jha and Panchayati Raj minister Kapildeo Kamat to rush to the accident
spot.
A team of SDRF (State Disaster Response Force) has reached the mishap site.
The chief minister issued instructions to provide all possible assistance to victims of the bus tragedy.