By Farid Ahmed
DHAKA, Bangladesh (CNN) -- Bangladesh headed to the polls Sunday, hours after overnight violence left three people dead, authorities said.
A polling official and two protesters were killed in attacks on polling stations Saturday night.
In one incident, attackers hurled a petrol bomb at a polling station in Thakurgaon district, local police superintendent Faisal Mahmud said. A polling officer was killed in that attack.
Two people died when police opened fire on a group that attacked a polling station in Rangpur district, police said.
Attackers have torched about 150 polling centers and election materials nationwide. Widespread violence has prompted the opposition to boycott the polls and call for a strike.
The largest opposition party, the Bangladesh Nationalist Party, and its allies called a two-day general strike for Saturday and Sunday, urging all to refrain from voting. The boycott would ensure a victory for the ruling Awami League party.
Bangladesh has seen a series of incidents of deadly street violence over the elections in recent months. Local civic groups and international communities urged the government to cancel the voting and reschedule the elections.
Protesters don't trust Prime Minister Sheikh Hasina and her administration, and want a neutral caretaker government to oversee the vote to make sure it is fair. But that caretaker system was scrapped a few years ago.
The election unrest underscores the persistent problems in the South Asian nation, a country grappling with grinding poverty, political instability and development challenges.
™ & © 2014 Cable News Network, Inc., a Time Warner Company. All rights reserved.