SARAJEVO (Reuters) - A Serb nationalist who opposes Bosnia as a state won a share of its tripartite presidency, election results showed on Monday, as Serb, Croat and Muslim ethnic parties dominated their regions in voting likely to slow the country’s march toward EU integration.

Milorad Dodik, of the Alliance of Independent Social Democrats, SNSD attends a news conference where he declared himself the winner of the Serb seat of the Tri-partite Bosnian Presidency in Banja Luka, Bosnia and Herzegovina October 7, 2018. REUTERS/Ranko Cukovic

The largest parties from Bosnia’s Serb, Muslim and Croat communities, which have been in power most of the time since its 1992-95 war ended, mostly entrenched their domination of all layers of Bosnia’s complex government.

Since the war, which killed 100,000 people, Bosnia has been divided between a Serb Republic and a federation of Croat and Muslim cantons, with a presidency formed of one member from each of the three main groups.

The solid grip of ethnic parties has frustrated efforts to reform the economy and win Bosnia admission to Western organizations such as the European Union and NATO.

“Yesterday’s election, much like previous elections in Bosnia, will serve to perpetuate the political deadlock and make the country’s EU and NATO accession difficult,” said Marko Attila Hoare, political analyst and Balkan historian.

The SNSD party of pro-Russian Serb nationalist Milorad Dodik was on course to be the strongest single party in Bosnia, and, along with coalition partners, set to dominate both the Serb caucus in the national parliament and the parliament of the autonomous Serb Republic.

Dodik, who campaigned on the secession of the Serb Republic and integration with Serbia, also won the Serb seat in the tripartite presidency of a country he has repeatedly denounced as an “impossible state”. His ally Zeljka Cvijanovic was elected to take over Dodik’s former job as president of the Serb region.

The largest Muslim Bosniak party SDA secured the most votes in Bosnia’s autonomous Bosniak-Croat Federation and its Bosniak Muslim-dominated cantons. Its candidate Sefik Dzaferovic won the Bosniak seat in the inter-ethnic presidency.

A coalition led by the largest Croat party HDZ won the most votes of Croats in the Federation parliament and in the majority Croat cantons. However, its leader Dragan Covic lost the seat in the presidency to Zeljko Komsic, seen as a more moderate figure, who Covic said won the vote thanks to votes of Bosniaks.

“It is not good that one people choose a representative of the other people,” Croatia’s Prime Minister Andrej Plenkovic said in Zagreb.

Hoare said the election meant “things will get worse before they get better, as the Republika Srpska, where Dodik has won another victory, may eventually make a bid for independence - possibly with Russian backing.”

INSTITUTIONAL CRISIS LOOMING?

More than two decades after the war, the leading Serb, Croat and Muslim Bosniak parties campaigned on nationalist tickets, reviving wartime pledges while failing to offer clearly defined economic or political visions.

International election monitors said the vote was generally orderly despite some reported violations, and called on the authorities to investigate all allegations of fraud and misconduct.

Mavroudis Voridis, the special coordinator of an observer mission from the Organisation for Security and Cooperation in Europe (OSCE), also said formation of institutions was uncertain due to a failure of the Bosniak and Croat parties to agree on changes to the election law before the vote.

“We expect all political leaders to engage in the formation of the governments at all levels, by working constructively together,” EU foreign policy chief Federica Mogherini and EU Enlargement Commissioner Johannes Hahn said in a joint statement.

The U.S. State Departments expressed concerns over reported violations of the voting process, including accuracy of voter registration rolls, impartiality of election observers, equitable access to media, and misuse of public resources.

“We expect all stakeholders and citizens to pursue any grievances through established legal channels,” spokesperson Heather Nauert said in a statement.

Dodik said on Monday his party would clinch a partnership with the HDZ in the Council of Ministers, which is the de facto national government, and in the national parliament.

“Bosnia is heading toward the institutional crisis when it comes to the presidency,” said Alida Vracic, the executive director of the Populari think tank, referring to the possible disagreement between Dodik and moderate Komsic.

But deals will be easier to make at other government levels where the three nationalist parties have ruled together over the years, Vracic added.