Nebi Bozov is to become the first mayor of Sarnitsa, Bulgaria's newest municipality, after a Sunday runoff vote results, electoral officials have now confirmed.

Sunday's election produced just a mayor of the southwestern municipality, with municipal councilor picked by voters back in the first round.

Bozov, who is backed by the liberal Movement for Rights and Freedoms (DPS) party, has garnered 60 percent of support, while his opponent supported by the main ruling, center-right GERB party, Mustafa Alikanov, has 40 percent of ballots cast in his favor.

The winner declared his victory as early as Sunday evening, but  there were no official estimates at the time.

This comes against the backdrop of a pledge by the Reformist Bloc, a right-wing government partner to GERB, that its voters will back Alikanov at the runoff vote.

RB's own candidate was third in the first round, when no single contender had outright majority.

Alikanov on Monday accused the RB of failing to mobilize enough voters to support him. He reminded that, if combined, first-results of GERB and RB-backed candidates outweighed the support for Bozov.

Bozov will however be forced to face the challenge of governing alongside a GERB-RB dominated municipal council, after the two parties earned a majority of seats in the first round.

The new mayor will be in office for just six months prior to regular local elections due across the country this autumn.

But a snap vote was held after Sarnitsa, an entity comprising one town and two villages of just five thousand people, "broke away" from the Velingrad municipality on January 1, 2015.

The vote in Sarnitsa is considered to be a "rehearsal" for the forthcoming local vote.

It also marked the first time a preference option was used to pick municipal councilors, with voters allowed to rearrange the list by singling out a certain candidate.