SOFIA, Tsetska Tsacheva, the presidential election candidate of Bulgaria's governing centre-right GERB party, leads her main rival, a voter survey before the Nov. 6 poll showed - but a runoff between the pair looks all but certain.
Neither parliament speaker Tsacheva nor Socialist candidate Rumen Radev would get the overall majority needed for a first round win, according to Monday's poll, by Alpha Research between Oct 8-13.
That raises the strong likelihood of a runoff which a survey published on Friday by Gallup International indicated Radev might win.
Bulgaria's presidency is a mainly ceremonial post, but next month's election has taken on a wider significance because GERB Prime Minister Boiko Borisov has said he will resign if his candidate does not score a first-round win.
According to Monday's poll, Tsacheva leads Radev - a former air force commander - by 29.3 percent to 21.4 percent. Some way behind in third, among 21 candidates in all, was Krasimir Karakachanov, a leader of the nationalist Patriotic Front party, on 8.7 percent
The Alpha survey did not ask voters who they would choose in a second round.
The Gallup poll did, and showed Radev three percentage points ahead of Tsacheva in a runoff, though with almost half of respondents indicating no preference for either candidate.
(Alpha Research and Gallup are independent polling agencies)
(Reporting by Angel Krasimirov; editing by John Stonestreet)