Bulgaria is holding its fourth parliamentary election in 18 months on Sunday, this time with galloping inflation and rising energy prices on the minds of voters.

Public opinion polls forecast that up to eight parties could clear the 4% hurdle for entry into parliament. Pro-Russian and nationalist parties such as Vazrazhdane (Revival) are expected to gain ground.

The biggest vote-getter is likely to be the center-right GERB party of former three-time Prime Minister Boyko Borisov, who left office after elections in April 2021 amid corruption allegations and street protests.

Polls show the centrist We Continue the Change (PP) party in second. Kiril Petkov, party leader, was serving as prime minister until his liberal-socialist government was toppled in a no-confidence vote in June, paving the way for Sunday's elections. A caretaker Cabinet now governs in Sofia.

A large pool of voters told pollsters they were undecided.

Even if Borisov's GERB places first, the win is unlikely to be big enough to govern alone. But finding coalition partners could prove tricky. The PP has already rejected a coalition with the GERB.

The fallout from Russia's war on Ukraine has dominated the election campaign in the southeastern EU country. The freeze on deliveries of Russian gas, rising prices and a dispute over arms deliveries to Kyiv have shaped the debate.

There were mutual allegations of corruption and incompetence, as well as personal insults, during the election campaign.

Under the slogan "Stronger than chaos," GERB has promised to curb inflation and to follow a consistent NATO and EU course. The party says the euro common currency will be adopted in 2024 under its watch.

The PP's motto is "Let's finish our work." By this, it means the fight against corruption and reforms to the judiciary, which Petkov had promised during his term in office.

Polling stations are open until 8 p.m. (5 p.m. GMT). Initial forecasts are expected soon after they close although official results are not expected until early in the week.