Preliminary official results show Nikolic, of the Serbian Radical Party, taking more than 31 percent of the vote yesterday.
Tadic, a former defense minister and leader of the Democratic Party, received more than 27 percent.
Nikolic expressed confidence he will win the 27 June runoff, while Tadic has called on pro-democracy forces to unite behind his candidacy.
Turnout in the election was about 45 percent.
It was the fourth presidential election in Serbia in less than two years. Three previous polls were invalidated because turnout didn't reach 50 percent -- a legal requirement which has been scrapped.
(compiled from wire reports)
Tadic, a former defense minister and leader of the Democratic Party, received more than 27 percent.
Nikolic expressed confidence he will win the 27 June runoff, while Tadic has called on pro-democracy forces to unite behind his candidacy.
Turnout in the election was about 45 percent.
It was the fourth presidential election in Serbia in less than two years. Three previous polls were invalidated because turnout didn't reach 50 percent -- a legal requirement which has been scrapped.
(compiled from wire reports)