Montenegro's Foreign Minister Igor Luksic has withdrawn from the race for the post of UN Secretary-General, the AP reported on Tuesday.

The move by Luksic, who came in last in the latest round of informal voting on candidates vying to succeed Ban Ki-moon, leaves 10 candidates in the race, including Bulgaria’s Irina Bokova.

Bokova, UNESCO Director-General, ranked fifth in second straw poll vote in the UN Security Council held earlier this month.

United Nations secretary-general Ban Ki-moon’s term of office will expire at the end of 2016.

In his letter, Luksic said that "for the sake of equal ownership of all the regions within the U.N. I hope the Eastern European argument will prevail when it comes to the final decision."

The informal tradition of regional rotation is a major factor in appointing the Secretary-General. No Secretary-General yet has come from Eastern Europe. 

A third straw poll in the selection of a United Nations Secretary-General will be held on August 29. The final decision will be made in October.

The fifteen members of the Security Council  vote "encourage", "discourage" or "no opinion" on the candidates, with the vote also aimed at persuading some of the contenders to leave the race.

Luksic is the second of 12 contenders for the UN top job to withdraw from the race. Vesna Pusi?, Croatia's former Foreign Minister, quit earier in August after coming in last in the first round of informal voting held last month.