Three of those who died are supporters of the opposition BNP after they were shot by police, said reports. An election official was stabbed to death by alleged BNP men.
The Bangladesh Nationalist Party (BNP) men also set on fire in more than 100 polling stations since Saturday till early Sunday, said reports.
The BNP is protesting against the decision of Prime Minister Sheikh Hasina of Awami League to do away with the practice of having a neutral caretaker government for supervising the polls.
Of the 300 parliamentary seats, 146 are being contested only as BNP has already boycotted the polls.
The voter turnout is low since morning when the balloting started at around 8 am since many chose to remain indoor fearing a violent election.
According to The Daily Star, at least three opposition activists were killed as police opened fire on them while they were trying to foil polls in Rangpur and Nilphamari early on Sunday.
A pro-BNP man, who was hurt in a clash with Awami League activists in Lalmonirhat on Saturday, succumbed to his injuries at Rangpur Medical College and Hospital on Sunday, the newspaper reported.
Worst violence is reported from Bogra district in the North where the BNP is powerful.
While about 150 people died in the past months in the run up to the polls, violence stuck the country a day before the polls as around 38 polling centres were burnt across the country on Saturday itself. Reports said more than 100 polling stations were torched by the Opposition supporters.
Violence was reported from different places in the country including Rajshahi city and Kishoreganj districts.
The BNP-led 18-party opposition alliance had earlier said that since the government did not cancel Sunday's polls it will be responsible for any untoward incident in the country.
"We urge people from all walks of life not to go to polling centres and boycott it," Osman Faruq, an adviser to BNP Chairperson Khaleda Zia, said.
"If the government does not cancel the January 5 elections and fails to 'free' Khaleda then the government will be held responsible for any unwarranted situation," he was quoted in the paper.
Polling will continue till 4 p.m. on Sunday.
--IBNS (Posted on 07-01-2014)