Five rivers are flowing above danger level at various places in Bihar. (AFP file photo)

The number of deaths in the Bihar floods rose to 24 on Monday, with 25.66 lakh people reeling from the deluge in 12 districts of the state following incessant rains in neighbouring country Nepal, officials said. Five children drowned on Monday in flood waters in two separate incidents in Bihar's East Champaran district, police said.

In the first incident, two children, aged just five and six years, drowned in a ditch filled with flood waters in Jaisinghpur village while they were playing.

Their bodies have been fished out and sent for postmortem, Turkauliya police station Station House Officer (SHO) Akhilesh Mishra said.

The children were identified as Ajit Kumar, 5, and Manu Kumar, 6, he said.

In another incident, three children including a girl drowned in a canal filled with flood waters in Budhwa village.

The children had gone to see rising water-level near the canal but slipped and fell into it after a portion of the earth under their feet caved in, Banjaria police station SHO Pramod Paswan said.

The children were identified as Arti Kumari, 10, Shubham, 7, and Brajesh, 9, Mr Paswan said, adding their bodies have been retrieved.

The five bodies have been sent to Motihari Sadar Hospital for postmortem, police said.

Of the 24 other deaths reported till 6 pm on Monday, Sitamarhi accounted for 10 deaths, while nine were reported from Araria, four from Kishanganj and one from Sheohar, a Disaster Management Department report said.

Four deaths were reported till Sunday evening from Araria (2), Sheohar (1) and Kishanganj (1).

With five rivers in spate, Chief Minister Nitish Kumar undertook his second aerial survey of the flood-hit areas during the day.

According to the Water Resources Department daily bulletin, five rivers -- Baghmati, Kamla Balan, Lalbakeya, Adhwara and Mahananda -- are flowing above danger level at various places in the state.

Baghmati river is flowing above danger mark at five places including Dheng, Sonakhan, Dubbadhar in Sitamarhi while at one place at Benibad in Muzaffarpur district, it said.

A Patna Meteorological Centre official said it has issued a warning of heavy rainfall in Supaul, Araria, Kishangaj, Purnea and Katihar in next 24 hours.

As many as 25,66,100 people have been affected by flood waters in 77 blocks of 12 districts -- Sheohar, Sitamarhi, East Champaran, Madhubani, Araria, Kishanganj, Supaul, Darbhanga, Muzaffarpur, Saharsa, Katihar and Purnea -- the report said. Saharsa, Katihar and Purnea districts are the latest addition to the list of the districts marooned.