All the inundated villages were in flood-prone districts of Muzaffarpur, Gopalganj, Purnia, Araria, Saharsa, Madhepura and Bagaha, officials said.
"Water entered these villages after levels rose in all the major rivers following heavy rains in the state and the catchment areas of Nepal," a water resource department official said.
According to the Central Water Commission, the water level in major rivers - Kosi, Mahananda, Gandak, Budhi Gandak, and Bagmati - has increased since Friday.
Kosi and Bagmati are flowing above danger mark at some places. "All the rivers are in full spate following heavy rains. Some rivers may cross the red mark late Saturday or Sunday," an official said.
Officials said that after two consecutive years of drought, the fear of floods is back in Bihar with incessant rains and heavy water discharge into the Kosi river from Nepal.
However, Bihar Water Resources Development Minister Vijay Kumar Choudhary said all embankments were safe and there was no need to panic. "The government is fully ready to face any eventuality if water level in rivers create threat," he told IANS.
Reports suggested that the authorities have asked hundreds of people to shift to safer places following the rising water level of the Kosi. The state government has asked engineers and district officials to keep a 24-hour vigil.
Choudhary said the eastern Kosi embankment, which had breached in 2008, flooding five districts of northern Bihar, was totally safe. "We are taking care of it. There is no need to panic."
In 2008, over three million people were rendered homeless in Bihar when the Kosi river breached its bank upstream in Nepal and changed course. It was said to be the worst flood in the state in the last 50 years.
According to the water resources department, a lot of water has been discharged into the Kosi in the last few days after heavy rains in Nepal since Monday.
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