Serbia faces a showdown next month between a nationalist who leans towards Russia and a liberal favoring the West in a presidential election run-off.
Both candidates oppose independence for the breakaway province of Kosovo expected to be declared after the second round vote -- a move Russia backs Serbia in seeking to block.
Nationalist Tomislav Nikolic took 39.6 percent of votes in the first round on Sunday in a field of nine candidates, ahead of 35.5 percent for pro-Western President Boris Tadic.
The two men will compete in the run-off on February 3, foreshadowing a repeat of the 2004 race which Tadic won with 53.2 percent.
Analysts said Sunday's 61 percent turnout -- strong by Serb standards and the highest since the fall of Slobodan Milosevic in 2000 -- showed how seriously people took the vote. Turnout could be even higher on February 3.
The second-round will require a maximum mobilization by both candidates, analyst Zoran Stojiljkovic told Belgrade daily Danas. We can expect a tight race and a decision in photo-finish, with Tadic having only a slight lead.
Nikolic is lukewarm towards European Union membership and argues that Serbia can steer a middle course between the 27-member bloc and Russia.
Tadic said Serbs must return to the polls in force on February 3 to show that Serbia is absolutely not giving up its European course, the path it started on in 2000.
He warns of dark days if Nikolic wins. His opponent denies accusations of isolationism.
Serbia voted today for both Europe and Russia, he told state broadcaster RTS. The road to Russia is at this moment more open, and I'll open the road to the European Union.
Serbia was never a close ally of Russia in the days of the Soviet Union, but Moscow's backing for its bid to block the independence bid by Kosovo has reinvigorated feelings of Slavic brotherhood against the West.
To win the second round, the candidates must also attract third party votes with promises of higher living standards and jobs, as well as promising to keep Kosovo, which is heading for independence with Western support.
Tadic strongly backs joining the EU, despite most EU members and Washington planning to recognize Kosovo -- Serbia's historic heartland -- as independent within months.
Many Serbs feel the country has paid enough for its role in the Yugoslav wars of the 1990s and most want EU membership. The question is whether their resentment is greater than the allure of EU-fostered economic development.
In the run-off, analysts think supporters of pro-Western candidate Cedomir Jovanovic will vote for Tadic while Nikolic would pick up roughly the same share of the vote from Milutin Mrkonjic, candidate of Milosevic's once-mighty Socialist Party.
Political analyst Milan Nikolic said the outcome might be in the hands of nationalist Prime Minister Vojislav Kostunica, the
backer of third-placed candidate Velimir Ilic.
Kostunica is Tadic's partner in Serbia's fragile coalition government but favors a hard line against the EU over Kosovo and is keen on closer political and economic ties with Moscow.
Kostunica is again in a position to decide the fate of the country, Milan Nikolic said.
(additional reporting by Ksenija Prodanovic; Editing by Charles Dick)