Bihar Chief Minister Nitish Kumar has order a probe into the police firing on flood victims in which one person was killed and three were critically injured in Madhubani district, official sources said on Saturday.

Some policemen were also injured in stone pelting by the flood victims.

Nitish Kumar directed Home Secretary Afzal Amanullah and ADG (CID) Yashwant Malhotra to visit Madhubani on Saturday and inquire into the incident.

The flood victims reportedly resisted a police bid to dig up land beneath a railway track to drain out flood water from Madhubani town and they reportedly threw stones at the police.

Madhubani district magistrate Rahul Singh said the incident took place when a mob blocked the drain to floodwaters from Madhubani town from flowing into Chakdah basti.

"The police opened fire in self defence," Singh told rediff.com over telephone. 

The injured were admitted to a government hospital here and their condition was critical, sources said.

Madhubani district is one of the 16 badly-affected districts in Bihar. The situation in the state remained grim on Saturday with the swollen river breaching its embankment at several places.

According to official sources in state disaster management department the flood claimed over 80 lives so far.