Bangladesh's chief election commissioner has rejected demands for a fresh vote after large numbers of complaints by opposition parties alleging that Prime Minister Sheikh Hasina's Awami League-led alliance rigged the ballot.
"It is not possible to hold a fresh election as the election was held in a peaceful manner," the commissioner, K M Nurul Huda, told reporters.
Ms Hasina has won a third straight term in the Sunday general election, sealing a landslide with almost all the seats in parliament, while the opposition rejected the result as rigged and called for a fresh vote.
The Grand Alliance won 288 out of 300 seats, Election Commission secretary Helaluddin Ahmed announced after the count was finished.
Ms Hasina is accused by her opponents of intimidation and the opposition disputing the outcome.
The Jatiya Party, led by former president HM Ershad won 20 seats, the opposition alliance led by prominent lawyer Kamal Hossain had only seven and others got three. The election of one seat was not held and results for another seat were halted by the commission.
The opposition rejected the outcome, with Mr Hossain calling the election farcical and demanding a new election be held under the authority of a "non-partisan government."
The opposition claims Ms Hasina's leadership has become increasingly authoritarian. More than a dozen people were killed in election-related violence on Sunday and the campaign preceding the vote had been dogged by allegations of arrests and jailing of thousands of Ms Hasina's opponents.
Mr Hossain said a few hours after voting ended that about 100 candidates from the alliance had withdrawn from their races during the day. He said the alliance would hold a meeting on Monday to decide its next course.
"We call upon the election commission to declare this election void and demand a fresh election under a nonpartisan government," Mr Hossain told reporters at a nationally broadcast news conference.
Calls by AP to several of Ms Hasina's aides seeking comment were not immediately returned.
Bangladesh's leading newspapers made banner headlines, some in red, while television stations aired round-the-clock analysis. The country's leading English-language Daily Star newspaper's headline was "Hat-trick for Hasina, BNP found missing in polling; atmosphere festive, tuned only to ruling party."
In an editorial, the newspaper narrated the poll environment broadly peaceful but criticised it, saying "this was a one-sided election."
"The blatant and starkest manifestation of an uneven state of affairs was the absence of polling agents of the opposition...in most, if not almost all, of the polling centres in the country," it said.
Ms Hasina's main rival for decades has been former Prime Minister Khaleda Zia, the leader of the opposition Bangladesh Nationalist Party, who a court deemed ineligible to run for office because she is in prison for corruption.
In Zia's absence, opposition parties formed a coalition led by Mr Hossain, an 82-year-old Oxford-educated lawyer and former member of Hasina's Awami League party.
The secretary general of Zia's party, Mirza Fakhrul Alamgir, won a seat in a twist victory. Mr Alamgir is a fierce critic of Ms Hasina and he spearheaded the formation of the opposition alliance with Mr Hossain at the helm. Mr Alamgir said he was rejecting any outcome, but it was unknown after his win was declared what he would do now.
In the run-up to the election, activists from both the ruling party and the opposition complained of attacks on supporters and candidates.
The Daily Star said on Sunday that 16 people were killed from 13 districts in election-related violence.
The Associated Press received more than 50 calls from people across the country who identified themselves as opposition supporters complaining of threats and being forced to vote in front of ruling party men inside polling booths.
Ms Hasina has expressed confidence in the outcome, inviting election observers and foreign journalists to her official residence on Monday.
While rights groups have sounded the alarms about the erosion of Bangladesh's democracy, Ms Hasina has promoted a different narrative, highlighting an ambitious economic agenda that has propelled Bangladesh past larger neighbours Pakistan and India by some development measures.
Voters "will give us another opportunity to serve them so that we can maintain our upward trend of development, and take Bangladesh forward as a developing country," Ms Hasina said after casting her ballot along with her daughter and sister in Dhaka.
On Sunday, some 104 million people in the Muslim-majority country were eligible to vote in Bangladesh's 11th general election since independence from Pakistan.
Both sides were hoping to avoid a repeat of 2014, when Zia and the BNP boycotted and voter turnout was only 22 per cent. More than half of the 300 parliamentary seats were uncontested. The Awami League's landslide victory was met with violence that left at least 22 people dead.
About 600,000 security officials, including army and paramilitary forces, were deployed to contain violence. The telecommunications regulator shut down mobile internet services nationwide to prevent the organising of protests.