The constituency became vacant after its MP Mahmud Us Samad Chowdhury died of Covid-19 in March
Voting in the bypoll to Sylhet 3 constituency began on Saturday morning amid tight security arrangements.
Polling began at 8am and will continue till 4pm without any break, said Regional Election Officer Foysal Quader.
So far, there has been no report of any violence.
According to the Election Commission, a two-member committee has been formed to ensure free and fair polling in the three upazilas – Fenchuganj, Dakshin Surma and Balaganj -- under the constituency.
Besides, three judicial magistrates have been appointed to oversee polling between September 2 and September 6.
As many as 21 executive magistrates are also on poll duty to maintain law and order. Some 17-18 members of law enforcement agencies, including the police and Ansar, are manning each polling booth.
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Meanwhile, mobile forces, comprising police, APBn, Ansar, 12 striking force, 12 teams of RAB and 12 platoons of Border Guard Bangladesh (BGB), have been deployed to ensure peaceful voting.
The constituency fell vacant after its MP Mahmud Us Samad Chowdhury succumbed to Covid-19 on March 11.
The bypoll was deferred twice due to a surge in Covid-19 cases.
On July 26, the High Court stayed the bypoll to the constituency till August 5 due to the worsening Covid-19 situation in the country. Later, the court asked the Election Commission to complete the bypoll by September 7.
Habibur Rahman Habib got the Awami League ticket for contesting while the other candidates -- Mohammad Atiqur Rahman of the Jatiya Party, Junaid Mohammad Mia of the Bangladesh Congress and Shafi Ahmed Chowdhury -- are in the fray as independents.
Some 350,000 people are eligible to vote in the bypoll.