Egyptian Culture Minister Hosni, 71, would be the first UNESCO secretary-general from an Arab country, but his candidacy has drawn criticism from Western intellectuals and Jewish groups due to comments he made in May 2008, in which he promised to burn any Israeli books found in Egyptian libraries.
The opposition to Hosni was led by Elie Wiesel, Bernard-Henri Levy and others, who blasted the candidacy of a "book-burner" and noted his 22 years as a minister in an authoritarian regime responsible, among other things, for censorship in his country. They also complained of his 2001 characterization of Israeli culture as "racist" and "inhumane."
Hosni has apologized for the book-burning comment, saying it came out of anger at Israeli treatment of the Palestinians and did not reflect his views on cultural pluralism.
He sought reconciliation "between all those who are divided," he told France 24 TV last week.
Bolkova, 57, is a former foreign minister of Bulgaria and currently the country's ambassador to France. Her candidacy started weakly, but has garnered much support as other contenders have dropped out of the race.
Six candidates for the four-year position have dropped out in the wake of the first three rounds of voting last week - European Union External Relations Commissioner Benita Ferrero-Waldner, Russian Deputy Foreign Minister Alexander Yakovenko and candidates from Lithuania, Ecuador, Benin and Tanzania.
AP contributed to this report.