MADRID - Voting is under way in Spain's third general election in four years.
The election is marked by the rise of the far-right movement Vox, which opposes multiculturalism and has threatened to end self-rule for regions like Catalonia.
Socialist Prime Minister Pedro Sánchez has presented himself as a bulwark against the advance of the hard right.
Polls suggest his party will lead the vote but no single group will win an overall majority.
The final opinion poll in El País newspaper on Monday put the Socialists (PSOE) at about 30%, the conservative People's Party (PP) at around 20%, the centre-right Ciudadanos and left-leaning Podemos both near 14% and the far right Vox party at about 11%.
However, the poll also showed that up to four in 10 voters had yet to make up their minds.
Voting began at 09:00 (07:00 GMT) and will end at 20:00 on the mainland.
An exit poll will be published when voting closes, but in the previous two elections this failed to give an accurate picture of the outcome.
Almost all votes are expected to be counted by midnight.
The highly polarised campaign was dominated by issues including national identity, gender equality and the future of Catalonia.
The semi-autonomous region held an independence referendum in October 2017 and declared its independence from Spain weeks later.
A dozen of its leaders have since gone on trial in Madrid, facing charges including rebellion and sedition.
Analysts say support for Vox has been boosted by widespread anger at the independence drive. The party fervently opposes any concessions to the secessionists.(FA)