Milan Jelic, president of Bosnia's Serb Republic died of a heart attack Sunday after less than a year on the job, the prime minister said. He was 51.

Jelic suffered a heart attack while watching a soccer game in his hometown, Modrica, his brother Slavko Jelic said in Serbia. The president was a former soccer player himself and was president of Bosnia's Soccer Federation.

"This is a sad day for Republika Srpska," Dodik told reporters, using the republic's official name.

Jelic was elected president of the Serb Republic — one of the two mini-states that make up Bosnia and Herzegovina — in October 2006. The other republic is the Bosniak-Croat Federation.

The presidency is a largely ceremonial position, with power lying in the hands of the government and its prime minister.

Born in 1956 in north Bosnia, Jelic earned a doctorate in economics and was the head of the Modrica oil refinery for 13 years.

He was a member of the Serb Democratic Party founded by wartime Bosnian Serb President Radovan Karadzic, who is now a war crimes fugitive. But in 1998, he switched to Dodik's party of Independent Social Democrats, currently the most influential Bosnian Serb party.

Before he was elected president, he served as minister for economy, energy and development in the Bosnian Serb government.

Jelic was "a good man and politician who died too early at a time when he could have contributed the most," said Mirsad Kebo, vice president of the Bosniak-Croat Federation.

In Belgrade, Serbian President Boris Tadic called Jelic "a good president and a true friend of Serbia."

Slavok Jelic said his brother had undergone a bypass surgery in 2003.

It was unclear who might succeed Jelic. Political analyst Tanja Topic said the Serb Republic's constitution does not make clear the chain of succession.

Among possible successors was Dragan Cavic, an ex-Bosnian Serb president and member of the Serb Democratic Party, who came second to Jelic in last year's elections. One of Jelic's deputies could also succeed him, Topic said.

The peace agreement that ended Bosnia's 1992-95 war divided the country two ministates, each largely autonomous, with its own president, parliament, police and army.

The two are linked by a central government, a parliament and a three-member presidency.

Jelic is survived by his wife, Milica, and son, Petar.