The candidate of the ruling right-wing GERB party Rosen Plevneliev was elected Bulgaria's next president in a run-off vote, the first official results showed.

Plevneliev, 47, who shot to popularity as former construction minister, won the second-round vote with about 52.5 percent, according to official results based on data from 98 percent of polling stations.

The Socialist candidate and European deputy Ivaylo Kalfin took about 47.4 percent, the results showed.

The central electoral commission will have to perform a second count of data from all stations before it can release full official results by Tuesday, its spokeswoman Ralitsa Negentsova told AFP.

About 50 percent of Bulgaria's 6.9 million eligible voters had turned out to cast a ballot in the presidential vote and parallel elections for local mayors.

Plevneliev and his vice-president, current Justice Minister Margarita Popova, were elected for a five-year term in office for the highly ceremonial job which carries limited real powers.

They will be sworn in on January 23, when incumbent Georgy Parvanov sees off his second and last term in office.