Spain's ruling Socialists are heading for victory in the third election in four years, but have fallen short of a majority, early results say.

PM Pedro Sánchez's party is to win almost 30% and would need the support of left-wing Podemos and nationalists to form a government.

For the first time since military rule ended in the 1970s, a far-right party is set to enter parliament.

Vox opposes multiculturalism, feminism and unrestricted migration.

The party polled over 9% of the vote, which would give it 23 seats in the 350-seat parliament, with 23% of the vote counted.

The Socialist prime minister has presented himself as a bulwark against the far right's advance.

According to the early results the Socialists are set to win 131 seats while their former coalition partner Podemos would have 39.

That would leave the two parties short of the necessary 176 for a majority, and requiring the support of Catalan pro-independence parties and Basque nationalists.

The Popular Party (PP), which ruled Spain until it was dumped from power in May 2018 in a no-confidence vote, is heading for its worst election ever, with just 65 seats.

That would leave the PP far short of forming a coalition with centre-right Ciudadanos (Citizens) and Vox.