Regional and municipal elections are taking place today in Spain, which will serve as an indicator for a general election at the end of the year.

More than 35 million people can vote in 12 regions and 8,000 towns and cities, where the ruling Socialist Party (PSOE) currently holds most of the power. The conservative People’s Party (PP) is expected to make gains, which could threaten the left-wing coalition government in the future.

The voting started at 9 a.m. (0700 GMT) and will end at 8 p.m. The campaign has been marred by several scandals, from accusations of electoral fraud in small municipalities to a rare case of abduction.

Many regions will have close contests, with no clear winners, according to election polls and experts, except for Madrid, where the PP’s regional leader Isabel Diaz Ayuso could secure an absolute majority.

The PSOE could lose some key regions, such as Valencia, which has almost 5 million inhabitants. The PP could also win in Aragon and the Balearic Islands, polls suggest.

The elections could also signal a shift back to a two-party system dominated by the PSOE and PP after years of increased participation from smaller parties such as the left-wing Podemos, the government’s coalition partner, and the centrist Ciudadanos. Both may fail to get the 5% vote required to enter many regional parliaments.

However, the PP may need the support of the far-right Vox to form governments in some regions, which could foreshadow a right-wing coalition government after the general election.