The Election Commission faces a daunting challenge to ensure peaceful elections for 57 seats in the fifth and final phase of the Assembly polls on Thursday thanks to widespread Left-wing extremism and porous border.

Voting will be held in 14,709 booths in Darbhanga, Madhubani, Supaul, Saharsa, Madhepura, Katihar, Araria, Purnea and Kishanganj. "The borders have been sealed to check influx of suspected troublemakers from the Nepal side," said additional chief electoral officer R. Laxmanan.

The voting time at the booths under Simri Bakhtiyarpur and Mahishi constituencies in Saharsa has been curtailed by two hours (It will be held between 7am and 3pm) because of Maoist threat. Two helicopters and three drones will be used for surveillance, Laxmanan added.

Since a number of polling booths are located in diara (river island) areas, the commission has deployed 50 Mounted Military Police (MMP) personnel to keep a watch on the movement of suspected troublemakers. In addition, 53 motorboats will be used to patrol the river.

The personnel of the Rapid Action Force (RAF) staged flag marches in bordering districts to instil confidence among voters ahead of the election. The police have been asked to remain extra vigilant and deal sternly with those trying to disturb the poll process, Laxmanan said.