Sofia, Bulgaria ? Bulgaria’s pro-Western president was forced into a runoff with a maverick ultranationalist who has fiercely criticized his efforts to lead the former communist country into the European Union, election results showed Monday.

President Georgi Parvanov won 64 percent of the vote in Sunday’s presidential election, compared with only 21 percent for his closest rival, Volen Siderov, results showed. But a runoff will be held Oct. 29 because voter turnout was too low to give Parvanov an outright victory.

According to election law, at least 50 percent of Bulgaria’s 6.4 million registered voters were required to cast ballots to guarantee a first-round winner, but only 42.5 percent showed up.

Voter apathy had been fueled by frustration with the tough economic and social reforms that ensured Bulgaria met requirements for EU membership. In the first post-communist presidential election in 1992, three-fourths turned out to vote.