The United Nations has voiced concern over the violence and alleged human rights violations in Bangladesh before, during and after recent elections held on December 30.

More than a dozen people were killed in election-related violence and the election campaign was dogged by allegations of the arrests and jailing of thousands of opponents of the newly elected Prime Minister Sheikh Hasina.

"There are worrying indications that reprisals have continued to take place, notably against the political opposition, including physical attacks and ill-treatment, arbitrary arrests, harassment, disappearances and filing of criminal cases," said Ravina Shamdasani, spokeswoman for the UN High Commissioner for Human Rights in Geneva.

Shamdasani called on authorities to carry out prompt, independent investigations and to take urgent measures to prevent further reprisals.

"Reports suggest that violent attacks and intimidation, including against minorities, have been disproportionately carried out by ruling party activists, at times with complicity or involvement of law enforcement officers," Shamdasani said.

Hasina's Awami League (AL) party won 96 percent of seats in Bangladesh's parliamentary elections on Sunday.

An AL-led coalition won a massive 288 seats, while the main opposition alliance dominated by the Bangladesh Nationalist Party (BNP) secured just six.

Hasina is set to form her third consecutive government and fourth overall.

The most prominent jailed opposition figure is Hasina's archrival, former Prime Minister Khaleda Zia, who was jailed for corruption in February 2018 - and deemed ineligible to run for office - on a charge her supporters say was politically motivated.

Curbing speech and media freedom

The Election Commission and other departments have been accused of overlooking complaints of irregularities.

In advance of the election, a new digital security law was enacted that raised concern it would curb speech and media freedoms.

Shamdasani noted that there have been troubling reports of media professionals being intimidated, injured and having their property damaged, as well as other constraints that have hindered free and public reporting on the elections.

At least two journalists have been arrested under the Digital Security Act in relation to their reporting on the election.

"The blocking of at least 54 news and other websites since December 10 and temporary internet restrictions around election day have constrained freedom of expression," Shamdasani said.

There have also been reports of police breaking up recent peaceful public protests calling for a rerun-election, and reports of arrests and cases filed under laws like the Digital Security Act.

"Restrictive legislation, including this Act, should be reformed so that human rights defenders, civil society, journalists and all members of the public are protected in their exercise of the freedoms of expression," Shamdasani said.

Voters' rights

New York-based group Human Rights Watch (HRW) has also urged an independent investigation into the alleged irregularities. The US, the EU and the UN all expressed their concerns.

"International donors, the United Nations and friends of Bangladesh should remember that elections are about the rights of voters, not those in power," Brad Adams, HRW's Asia director, said in a statement.

In Zia's absence, opposition parties formed a coalition led by Kamal Hossain, a former member of Hasina's Awami League who was foreign minister under Hasina's father, Sheikh Mujibur Rahman, Bangladesh's founding leader.

Hossain's small party, Gono Forum, does not have much popular support. Hasina and Zia, on the other hand, have much larger support bases and attract hundreds of thousands of supporters to their rallies.

A day after the election, during a briefing with foreign journalists and election observers, Hasina came down heavily on the opposition. She refused a suggestion that she offer her political foes an olive branch.

"The opposition you see, who are they? The main party, BNP, it was established by a military dictator (Zia's husband, Ziaur Rahman) who introduced martial law in this country. There were no constitutional rights for the people," Hasina said.

She dismissed questions about the fairness of the vote and said it was a "very peaceful election".