The president of Bosnia's Serb Republic has died of a heart attack in hospital in central Bosnia, doctors and politicians have said.
Milan Jelic, 51, was elected last October at the ceremonial post of the region's president, following the general election.
"President of Republika Srpska Milan Jelic has died," Milorad Dodik, the Serb Republic prime minister, said in Banja Luka.
Bosnia is made-up of the Serb Republic and the Muslim-Croat federation, two autonomous regions created under the 1995 Dayton peace accords that ended a three-year war.
Jelic, a businessman and economist, was a regional minister of economy and industry in the previous government.
The constitution is unclear about who may succeed Jelic, said Tanja Topic, a political analyst, on Sunday.
Topic said candidates for the vacant post could include Dragan Cavic, the former Bosnian Serb president and a member of the Serb Democratic Party.
Cevic received the second-highest number of votes after Jelic, in October's presidential election.
Candidates could also include Jelic's deputies - Davor Cordas, a Bosnian Croat, or Adil Osmanovic, a Muslim Bosniak.