SOFIA, Bulgaria — Bulgarians began voting in an early election that has the Balkan country’s two main parties, Gerb and the Bulgarian Socialist Party, locked in a dead heat.

The Organization for Security and Cooperation in Europe and the Party of European Socialists have election monitors stationed at polls following reports of vote buying during presidential elections in October.

Bulgaria, the European Union’s poorest member, was thrown into turmoil in February by anti-austerity protests that echoed unrest across Europe. The next Cabinet needs to boost growth and continue budget cuts after unemployment rose to an eight-year high and violent rallies against poverty, graft and high utility bills led to the last government’s collapse.

“The elected parties will produce a very unstable Parliament and government,” Kolyo Kolev, head of the Mediana research institute in Sofia, said by phone. “These elections will be dirty, full of fear, pressured voting and vote buying.”

Bulgarian prosecutors are investigating 17 cases of alleged vote buying, the Office of the Chief Prosecutor in Sofia said on its website today. People living in a poor quarter of the city of Pernik, about 18 miles south-west of Sofia, received about $133 each to celebrate Orthodox Easter May 5, from one of the two biggest parties, Darik Radio reported today, citing its own correspondent in Pernik.

Former Prime Minister Boyko Borissov’s Gerb party, which lost control of the government on Feb. 20 amid the street protests, is in a virtual tie with the Socialists party, according to recent polling.

Gerb, which stands for Citizens for the European Development of Bulgaria, would probably win about 100 seats in the 240-seat assembly, while the Socialists will take about 80 seats, Otilia Simkova, an analyst in Eurasia Group in London, said in a report based on the recent polling.

Gerb’s most likely coalition partner would be the Bulgaria for Citizens Movement of former EU Commissioner Meglena Kouneva should it win the required 4 percent to enter Parliament, according to Simkova.

The Socialists, who have said former Finance Minister Plamen Oresharski would lead the government if they prevail, would probably forge a coalition with the ethnic Turk Movement for Rights and Freedoms and Kouneva’s party, Simkova said.

“The coalition government that succeeds” the interim Cabinet “after the election, whatever its political makeup, is likely to preside over a change of policy emphasis, if not a complete overhaul,” the Economist Intelligence Unit said in a report on May 9. “It will probably give greater emphasis to tackling unemployment and promoting economic growth, without jeopardizing the country’s prized fiscal stability."