Nationalist candidates of Bosnia's Croats, Muslims and Serbs were ahead in the race for the country's tripartite presidency, official partial results showed early Monday.
Bakir Izetbegovic, head of the main Muslim SDA party, looked set to win his second term as the Muslim member of the presidency.
Izetbegovic, son of Bosnia's late wartime leader Alija Izetbegovic, won 33.16 percent of the votes, according to results based on almost 77 percent of ballots counted.
His main opponent, local media mogul Fahrudin Radoncic, garnered 26.67 percent, the early results from the electoral commission showed.
Zeljka Cvijanovic and Dragan Covic were leading the race for the Serb and Croat member of the presidency respectively, both from nationalist parties.
However, race between them and their main opponents was a bit tighter.
Bosnians voted in general elections Sunday amid mounting social discontent over endemic corruption, ethnic disputes and economic woes that have troubled its rapprochement with the European Union.
Nearly 20 years since a devastating war between its Croats, Muslims and Serbs, Bosnia-Hercegovina is one of Europe's poorest nations and remains split along its ethnic lines.
The 1992-1995 conflict, which killed 100,000 people, left the former Yugoslav Republic divided into two semi-autonomous entities -- the ethnic Serb Republika Srpska and the Muslim-Croat Federation -- linked by weak central institutions.
Apart from the tripartite presidency, some 3.3 million voters were eligible to cast ballots to elect a new central parliament. They were also electing assemblies for the two entities and a president in Republika Srpska.
More results were to be announced later Monday, the electoral commission said.
- Nationalist pitch -
As always ahead of elections here, politicians returned to nationalist rhetoric to woo voters, notably the Bosnian Serbs.
Their nationalist leader, Milorad Dodik, running for a new term as Republika Srpska president, renewed threats that his entity might secede.
"The aim of my policy is that we are less and less an entity and more a state!" Dodik told a recent electoral rally.
Ivana Saric, a student from Sarajevo, said she had voted for a small, multi-ethnic party. But she said she did not believe many would follow her example.
"People are afraid to vote for major change, possibly because they are traumatised by the past. Twenty years ago they chose democracy. That brought them independence and then, later, war."
Earlier Sunday Izetbegovic, 58, said he expected voters to choose leaders capable of "overcoming the current deadlock that blocks the country's integration into EU and NATO... and pull it out from economic slump."
- EU deadlock -
Bosnia's economic doldrums form a grim backdrop to the vote, with an official unemployment rate at 44 percent and an average monthly salary of 415 euros ($525).
Corruption that has plagued the country since its inception now costs taxpayers some 750 million euros annually, according to non-governmental organisations.
Growing public discontent escalated in February into the kind of popular uprising not seen since the brutal conflict of two decades ago.
Thousands took to the streets to protest the government's failure to fight graft and introduce political and economic reforms needed for the country to gain EU membership.
Major floods in May, which caused an estimated two billion euros in damages -- roughly 15 percent of Bosnia's gross domestic product -- have further aggravated the economic situation.
And Bosnia's EU aspirations have been put on hold by political deadlock since 2006 due to ethnic tensions.
Politicians from the three major ethnic groups have failed to agree on reforms needed for membership in the 28-nation European bloc, leaving Bosnia lagging behind its fellow Balkan countries.
Political analysts warn that incoming elected officials will have to act quickly to prove their worth to a public which is otherwise likely to stage a new round of protests.
Ahead of the vote an EU statement said Bosnians should expect their elected officials "to bring much needed reconciliation in society and politics... close the gap with rest of the region and ensure progress towards the EU".
Turnout was 54.14 percent, around two percentage points lower than at the 2010 polls, official figures showed.