DHAKA - Bangladesh's main opposition party pulled out of mayoral elections on Tuesday saying the polls were rigged, deepening a political crisis plaguing the impoverished country.
The Bangladesh Nationalist Party (BNP) announced it was boycotting the elections in the two largest cities of Dhaka and Chittagong, more than four hours after voting got under way.
The polls are seen as a key test of the popularity of Prime Minister Sheikh Hasina and her centre-left ruling Awami League party, which the BNP says is becoming increasingly autocratic.
"We're formally announcing that we are withdrawing from these elections. There were riggings in 98 per cent of the voting booths," BNP spokesman Moudud Ahmed told reporters at party headquarters in the capital Dhaka.
"Our polling agents were not allowed to enter voting booths. Some were kicked out while others were arrested. This is no election. Once again it was proved that there is no democracy in this country," he added.
Local media reported irregularities, violence and ballot-box stuffing while voting was suspended in at least two centres in Dhaka.
Election Commission spokesman S.M. Asaduzzaman said he had not heard of any complaints by candidates of rigging.
In a statement, the United States Embassy in Dhaka urged the government to investigate the irregularities.
"We are disappointed by widespread, first-hand, and credible reports of vote-rigging, intimidation and violence that have occurred at polling stations today, and the BNP's decision to boycott the city corporation polls," it said.
"It is important that irregularities be investigated transparently and impartially, and we call on all parties involved to work within the law and avoid violence at all costs."
The BNP boycotted a general election in 2014 but has returned to politics recently after three months of crippling protests aimed at toppling Hasina failed to unseat her.
The opposition party, led by former premier Khaleda Zia, accuses Hasina of cracking down on dissent since her controversial walkover re-election in January last year.
It has ruled the country three times and was hoping a strong showing in the city polls would add momentum to a long-running campaign to force new national elections.
But Tuesday's boycott is likely to further entrench a political crisis pitting the families of Zia and Hasina, who are known as the "Battling Begums".
Bangladesh has been plagued by unrest for the last two years and has a long history of deadly political violence.
Scores of people have been killed in firebomb attacks on vehicles since the start of the year, when Zia called a transport blockade as part of her efforts to force the government to hold fresh elections.
More than 120 people died as opposition activists firebombed hundreds of buses and trucks and police responded by firing live rounds.
The BNP claimed last week that Zia, 69, had been the victim of an assassination attempt when the car in which she was travelling was shot at from close range.