President Boris Tadic signed a decree earlier this week to dissolve parliament and call early elections.
The move came after the ruling coalition had collapsed following Prime Minister Vojislav Kostunica's refusal to govern alongside Tadic's Democratic Party due to insurmountable differences on the issue of European integration.
"Mr. Kostunica shall not be prime minister in a Democratic Party government," President Tadic said in an interview with Belgrade-based daily Blic on Friday.
Tadic explained that his unwillingness to see his political opponent in the premier's seat was motivated by a move by Kostunica's Democratic Party of Serbia (DSS) toward unilateral cooperation with the nationalist Radical Party.
The Radical Party proposed a parliamentary resolution to freeze EU membership talks over the recognition by more than half of the EU's member states of Kosovo's recent unilateral declaration of independence from Serbia.
"I am not closing the door to anyone who could contribute to the process of European integration and the preservation of our territorial integrity," Tadic said. "That is why I reject cooperation with those leading Serbia into isolation, and why I am ready to cooperate with all those ready to achieve these two goals."
Asked whether the DSS and the radicals could form a coalition, Tadic said: "That danger has existed all these years. The DSS has never rejected such possibility and I have been constantly worried about this."
Tadic won a narrow victory over the Radical Party's Tomislav Nikolic in the February 3 presidential elections, a result received by analysts as a sign of deep division in Serbia between pro-Western elements looking to a future in the EU and hard line nationalists.
Tadic reiterated his party's commitment to the preservation of territorial integrity, saying that, "We are all for the preservation of Kosovo [as a part of Serbia] and I am convinced that we can only join the EU with Kosovo in Serbia."
He said that in two months Serbs would once again have the opportunity to confirm that "we want to join the EU."
