Incumbent Serbian leader Boris Tadic and his main challenger, Tomislav Nikolic, are headed for a runoff vote for the presidency after independent pollsters put Tadic slightly in the lead after the May 6 vote
The unofficial complete count of The Center for Free Elections and Democracy showed Tadic, of the pro-EU Democratic Party, taking 26.7 percent.
Progressive Party leader Nikolic, who says Serbia should not be an EU member if that means giving up its claim on former province Kosovo, won 25.5 percent.
Despite the ever-present Kosovo issue, anger over Serbia's economic struggles appeared the driving force in the vote, which saw support for the Democratic Party candidate crumble from 38 percent in the 2008 election.
One-quarter of the country's workforce is jobless.
The results were similar in the parallel parliamentary vote, which saw Nikolic's party edging out Tadic's Democrats, earning 24 and 22.3 percent of the vote, respectively.
Turnout was reported at around 60 percent.
Tadic and Nikolic have each predicted that they will win the runoff, which is set for May 20.
"As for my position, as I did in the previous election, I'm not going to accept any conditioning or blackmailing," Tadic said. "I'm expecting the support of citizens. I believe that citizens will give even stronger support than in first round to the policies which I have proposed."
Meanwhile, Nikolic said Tadic should be prepared to make concessions given the losses sustained by the Democrats.
The Socialists finished in third in the May 6 presidential and parliamentary contests, winning some 15 percent in each vote. That represents a doubling of their support compared to the previous election which, according to analysts, makes them the kingmakers in the formation of a new government.
While the Socialists are widely expected to join the Democrats, as they did after the previous elections four years ago, party leader Ivica Dacic said they now have the strength to demand the prime minister post.
"Maybe Serbia doesn't know today who will be president, but it knows who will be prime minister," the former spokesman for Yugoslav strongman Slobodan Milosevic told supporters in Belgrade.
WATCH: Serbs go to the polls in parliamentary and presidential elections on May 6.
Franz-Lothar Altman, the head of the Western Balkans section at the German Institute for International Politics and Security in Berlin, told RFE/RL's Balkan Service that a renewal of Tadic's coalition could allow for more leniency in his position on Kosovo.
"It may be [Tadic] will be willing to make more concessions now if his coalition is reestablished -- that he says, 'OK, now we have another four years, so we now can, in the beginning, move a little bit more in order to get the next step into the EU,' which means the start of negotiations [with Kosovo]," he said. "That could happen."
Kosovo, formerly an ethnic Albanian-majority province of Serbia, declared its independence in 2008 -- a move which Belgrade has refused to recognize. Progress in relations between Serbia and Kosovo, which the EU recognizes, is seen as crucial to Serbia's further progress toward joining the bloc.
Tensions were high in Kosovo on May 6, as minority Serbs defied ethnic Albanian authorities and participated in the Serbian elections.
The European Union congratulated Serbia for holding what it described as “free and peaceful parliamentary and presidential elections.”
Maja Kocijancic, a spokeswoman for EU foreign policy chief Catherine Ashton, told journalists that Serbia's new government should be committed to the European Union.
"We are now looking forward to a rapid formation of a new government that will be committed to reforms and will work for the progress on the path to the European Union," Kocijancic said.
Kocijanic also thanked the Organization for Security and Cooperation in Europe for facilitating the vote in ethnic Serb-dominated areas of Kosovo and said that works on further cooperation between Serbia and Kosovo would continue.
With reporting by RFE/RL's Balkan Service, Reuters, and AP