The bypoll to Bihar's Bhagalpur and Nalanda parliamentary constituencies passed off peacefully on Monday, amidst tight security with an estimated 35-40 percent voters exercising their franchise.

No untoward incident was reported from anywhere in the constituency, though there were reports of voters bycotting the by-elections in about a dozen polling stations in the two constituencies to protest against local problems like bad roads, Bihar's additional chief electoral officer V S Lal said.

Former Rashtriya Janata Dal MLA from Biharsharif in Nalanda, Naudhad-un-Nabi alias Pappu Khan was taken into custody till conclusion of balloting for allegedly forcing the people to cast their votes in favour of independent candidate Arun Kumar, who is being backed by his party.

The votes on Monday will decide the fate of eight candidates, including former union minister Syed Shahnawaz Hussain of BJP, former MP from Munger Shakuni Chaudhary (RJD) and Subodh Roy of CPI-M, also a former Lok Sabha member.

The by-poll in Nalanda and Bhagalpur was held following the resignation of Nitish Kumar and Sushil Kumar Modi on becoming chief minister and deputy chief minister respectively.