Bangladesh's main opposition party boycotted mayoral elections in the country's three main cities during voting on Tuesday.
The Bangladesh Nationalist Party (BNP) of former prime minister Khaleda Zia withdrew from the elections, in the capital Dhaka and port city Chittagong, alleging mass vote rigging.
Political uncertainty has prevailed since January 2014, when Prime Minister Sheikh Hasina's Awami League won a second consecutive term after a bloody parliamentary election boycotted by the main opposition.
The BNP has stepped up protests this year to try and force Hasina to step down and hold a new vote after last year's poll, deemed by international observers to be flawed.
Tuesday's mayoral elections were for two city corporation posts in Dhaka, the capital, and one in the port city of Chittagong, with a total of 6 million voters eligible.
The elections were supposed to be nonpartisan, but both the ruling party and the BNP directly backed candidates.
"This is not an election," senior BNP leader Moudud Ahmed told reporters. "The ruling party are voting for themselves by capturing polling centres."
Local media reported allegations of irregularities and ballot-box stuffing while voting was suspended in at least two centres in Dhaka.
The ruling Awami League promptly responded to the allegations, claiming the boycott was a ploy by the opposition.
"Khaleda Zia had this plan beforehand to boycott the election, she knew she would lose the poll. She had no intention to participate in the election," said Mahbubul Alam Hanif, the joint-General Secretary of the Awami League.
He also accused Zia of organising herself three attacks on her motorcade during campaigning last week.
The United States urged impartial investigation of election irregularities, underlining the need to avoid violence.
Khaleda and leaders of her party had vowed retaliation if the local elections were rigged.
The Bangladesh Nationalist Party boycotted January 2014 elections, claiming that they feared electoral fraud, but the election still went ahead.
Her party renewed their complaints and demanded a new election on Jan. 5, the disputed election's first anniversary, sparking a three-month period of political violence that saw more than 140 people killed and the country brought to a standstill.
Security had been tightened for the mayoral election with extra security forces deployed and vehicles banned from operating within the cities until midnight.
The boycott is likely to further entrench a political crisis pitting the families of Zia and Hasina, who are known as the “Battling Begums.”