Officials results in Bulgaria show conservative ruling party candidate Rosen Plevneliev won Sunday's presidential election, but without enough votes to avoid a runoff.

With nearly all the ballots counted, Plevneliev has 40 percent of the vote. His closest challenger, Socialist Ivailo Kalfin, has 29 percent. The two will face off again Sunday in a second round.

Plevneliev is a former construction minister whom many Bulgarians credit with upgrading the country's crumbling roads and infrastructure.

But the opposition Socialists accuse the ruling GERB party of stalling key reforms.

Bulgaria is experiencing only modest economic growth with unemployment a major problem. But the country is not expected to seek an economic bailout like several much larger and richer European Union economies.

Bulgarian officials say overall the election was problem-free. European election observers also say the voting ran smoothly. But they say they are concerned by widespread allegations of vote buying. They also note a lack of independent local media coverage of the elections.

The winner of the election will replace President Georgi Parvanov, who is barred by the constitution from seeking a third five-year term.