Election authorities in Sarajevo have ordered ballot boxes to be unsealed, and a recount at around 1,000 polling stations.
Thousands of people rallied Sunday in Bosnia for the second time in a week, alleging that a pro-Russian Bosnian Serb leader rigged a ballot during a general election in the Balkan country earlier this month.
The 2 October election was held for all levels of government in both the Serb-dominated and Bosniak-Croat parts of the Balkan country, as well as for the joint central institutions.
Final results are yet to be announced, although leading Bosnian Serb politician Milorad Dodik has claimed victory in the election for the post of presidency of the Serb entity.
Opposition leaders, however, claim that their candidate Jelena Trivic is the winner, and that Dodik rigged the ballot.
Citing reports of irregularities, central election authorities in Bosnia's capital Sarajevo have ordered the unsealing of ballot boxes and a recount at around 1,000 polling stations throughout the country before establishing the final tally.
Dodik, the most powerful politician the Bosnian Serb's semi-autonomous region, has denied allegations that he orchestrated an election fraud to rob his main challenger of her election triumph.
At a rally on Sunday in the northern city of Banja Luka, Trivic said the opposition wants a recount and a check of all ballots in the Bosnian Serb entity, and an investigation into possible vote-rigging.
“It wasn't me who was robbed, it was the people,” said Trivic. “We will not back down, we won't stop.”
The crowd chanted “Mile thief!,” referring to Dodik by his nickname.
Dodik has ruled practically unchallenged for years despite being sanctioned by the West for advocating the separation of Republika Srpska, as the Serb entity is called, from the rest of Bosnia.
Russia has backed Dodik, fueling fears in the West that Moscow might try to create further instability in volatile Bosnia to avert some attention from the war in Ukraine.
Separatist ambitions among ethnic Serbs sparked the devastating 1992-95 war in Bosnia, which killed more than 100,000 people, displaced millions and shattered the country for years to come.
A US-brokered peace agreement that ended the war created the Serb and Bosniak-Croat entities, tied loosely by joint institutions.
The Balkan nation of 3.3 million people remains plagued by corruption and ethnic tensions that have impeded efforts to join the European Union.