Mr Zoran Zivkovic, an ally of Serbia's reformist assassinated prime minister Mr Zoran Djindjic, emerged today as the murdered premier's likely successor.
Mr Zivkovic promised that Belgrade would keep up with Mr Djindjic's reforms, insisting that "political stability is a necessity".
Mr Zivkovic today told party officials that the country's politicians must assume responsibility for "a healthy Serbia".
"We have to use this moment, not for us or our party, but for Serbia, whom we see as the leader in the Balkans, a [future] member of the European Union, a state with strong democratic institutions," the 42-year-old said.
Mr Zivkovic also vowed to continue Serbia's co-operation with the UN war crimes tribunal.
The incoming prime minister still needs the Serbian parliament's vote of approval, expected in the coming week. And while popular and enjoying the support of reformers, he will need help from a wide range of experts if he takes office.
Mr Zivkovic will also head the Democratic party (DS), the leading force in Serbia's ruling DOS coalition, on an interim basis until its congress due to be held next year.
The party session began with a tribute to Mr Djindjic, shot dead on Wednesday by a single sniper's bullet in downtown Belgrade. A large photo of the slain prime minister, surrounded with flowers, was placed at the seat he usually occupied during party sessions.
Mr Djindjic headed up the 18-member DOS, which, while instrumental in overthrowing war crimes suspect Mr Slobodan Milosevic in October 2000, has been deeply split in the past months.
The selection of the prime minister's successor comes a day after Djindjic was laid to rest with the highest military honors with hundreds of thousands of mourners marching silently in the streets of the capital.
AFP