Bihar sharif and Sasaram violence occurred after Ram Navami processions.
Tension prevailed in Bihar even a day after Ram Navami as fresh violence was reported in Rohtas and Nalanda districts yesterday, the police said.
In Nalanda's Biharsharif, one person was killed and several others injured after clashes broke out between two groups last evening, while six people were injured in a blast in Sasaram town of Rohtas district.
Police said the blast occurred at a house in Sasaram and that they have recovered a two-wheeler from the site. "The injured are being treated at a hospital in Sasaram and investigation is on," an official said.
Police have imposed prohibitory orders in Nalanda to maintain law and order in the region.
Clashes were first reported in the two districts on Friday.
The tension had been building since Thursday over taking out Ram Navami processions. By Friday afternoon, the tension spiralled into a full-blown clashes, with the groups attacking each other with stones.
Shashank Shubhankar, District Magistrate, Nalanda said at least 80 people have been arrested and meetings are being organised by community leaders urging people to maintain peace.
Security has been increased in Nalanda and Rohtas and senior officials are present in the affected areas, they said, adding that social media is also being monitored to prevent the spread of any false or provocative news.
The home ministry has decided to send additional paramilitary forces to Bihar after violence in the state.
Amit Shah, who was scheduled to visit Sasaram today, spoke to Bihar Governor Rajendra Arlekar this morning to take stock of the current situation in the state.
Mr Shah had cancelled his trip following communal tension in the area.
Police also rubbished the reports claiming that some residents from Sasaram were leaving the region amid tension. Calling the reports "totally baseless and absurd", Rohtas Police urged people not pay heed to "any such rumour".
Bihar Chief Minister Nitish Kumar alleged that communal tensions in the state were triggered by some people indulging in "gadbad" (mischief).
"Communal tensions during Ram Navami festivities at Sasaram and Bihar Sharif are disturbing. Such incidents happened for the first time in the area. It's not natural," Mr Kumar said.
He said police officials have been instructed to identify those who are indulging in mischief and to "take strict action against them".