Awami League mayoral candidate Talukder Abdul Khalek was unofficially declared elected in the Khulna City Corporation (KCC) election on Tuesday.
The voting was suspended in the remaining three centres due to violence, capturing of polling stations and forced stuffing.
Returning officer Yunus Ali made the announcement around 9:40pm.
The voting began at 8am and ended at 4pm without any break. The turnout of voters was said to be around 50 percent.
The returning officer said voting in two polling centres - Labanchora Government Primary School and ward-31 councillor office - was suspended around 2:20 pm due to snatching of ballot papers and forced stuffing.
Besides, voting was suspended at Khulna Govt Iqbal Nagar School centre in ward No 24 following snatching of ballot papers by miscreants around 10:30 am, said presiding officer Khalilur Rahman.
Meanwhile, voting at Fatema High School in ward No 22 was suspended for two hours from 10:30am following an incident of fake voting.
Two bombs were blasted in front of the Khulna Government Women College polling centre around 3:30 pm, halting balloting for some time.
Talukder Abdul Khalek cast his vote at Pioneer Girls' High School polling centre around 8:07am.
BNP mayoral candidate Nazrul Islam Manju alleged that the ruling party men drove his polling agents from at least 40 centres.
He also alleged that his agents were obstructed from entering polling centres in ward No 22.
Besides, the ruling party men beat one of his polling agents at Zila School centre, he said.
At a press briefing at BNP's Nayapaltan central office, BNP senior joint secretary general Ruhul Kabir Rizvi alleged that ruling party men resorted to various irregularities in 50 percent of polling stations.
A total of five mayoral candidates, 148 general councillor and 38 reserved-seat female councillor candidates were there in the election race.
The mayoral contenders were Awami League's Talukder Abdul Khalek, Nazrul Islam Manju of BNP, Jatiya Party's Shafiqur Rahman Mushfiq, IslamiAndolan Bangladesh's MaulanaMozammil Haque and CPB's Mizanur Rahman Babu.