SOFIA, Bulgaria — Bulgarian Prime Minister Boiko Borisov announced Wednesday that the government is nominating its European commissioner, Kristalina Georgieva, as a candidate to be United Nations Secretary-General, replacing its previous candidate, UNESCO chief Irina Bokova.

The decision came two days after Bokova, came in sixth of nine candidates in the Security Council’s latest informal poll to succeed Ban Ki-moon on Jan 1.

Earlier this month, Borisov said his government would continue backing Bokova’s candidacy only if she was among the top two candidates in the fifth “straw” poll on Sept. 26.

“We made huge efforts, not only the government, but also the president, the foreign ministry and Irina Bokova herself, but you see the result,” Borisov said at the government meeting.

In order to be replaced, however, Bokova would need to file a letter announcing her withdrawal. She said she sees no reason to do that.

“None of the other candidates, even those with worse results, is doing it because the real race is still ahead,” Bokova said in an interview for the daily 24 chasa on Wednesday, before the prime minister’s announcement.

Under the U.N. Charter, the secretary-general is elected by the U.N. General Assembly on the recommendation of the Security Council. In practice, this means the votes of the five veto-wielding permanent members of the U.N.’s most powerful body — the United States, Russia, China, Britain and France — are critical.

By tradition, the job of secretary-general has rotated among regions. Asia, Africa, Latin America and Europe have all held the post. East European nations, including Russia, argue that they have never had a secretary-general and it is their turn.

There has also never been a woman secretary-general and more than 50 nations are campaigning to elect the first female U.N. chief, along with many organizations.

In Monday’s informal poll, Portugal’s former Prime Minister Antonio Guterres retained first place and was the only candidate to get the minimum nine required “yes” votes.

The key question for Guterres is whether one of the permanent members opposes his candidacy. That should become clear in the sixth straw poll expected next week which will be the first to distinguish the votes of the permanent and non-permanent council members.

One of the big question marks is who Russia will support. Borisov spoke to Russian President Vladimir Putin on Tuesday, before he announced the government’s support for Georgieva.

Bokova said in the interview that calls for her to leave the race are undignified. She added that “with a second candidate, Bulgaria will become a laughing stock.”

Since entering the race, Bokova has been a controversial candidate in Bulgaria because of her communist past.

“It appears that my successful start was not liked by certain circles in Bulgaria and outside Bulgaria. They saw that I have a chance to win and launched a negative campaign against me,” she said.

“Regretfully, I am the only candidate facing a hysterical campaign of name-calling and slander in my own country.”

In Brussels, Georgieva’s boss, European Commission President Jean-Claude Juncker, has granted her an unpaid leave of absence for the month of October to stand for the U.N.’s top post.

Commission spokesman Margaritis Schinas said the EU’s executive arm will “ensure a strict separation between activities relating to her candidacy and her work” at the commission, where she has the portfolio in charge of budgetary affairs and human resources.

Bulgarian Foreign Minister Daniel Mitov said the government will be seeking support for Georgieva from neighboring countries.

“I want to thank Ms Bokova, but we must transfer our support to Kristalina Georgieva,” Mitov said.

Associated Press writer Edith M. Lederer at the U.N. contributed to this report.