Iran Press/Europe: The conservative Popular Party (PP) came in second, and far-right Vox more than doubled its seats to become the country's third most-powerful party.
This is Spain's fourth general election in as many years, BBC reported.
A previous vote in April ended with no clear majority, and the Socialists failed to form a coalition government.
This time, the Socialist party won 120 out of a total of 350 seats - three fewer seats than in April's vote. The PP has 88 seats, up from 66 in the previous poll, while Vox has 52 - up from just 24 in April.
After failing to form a government, Sánchez had hoped that calling another election would strengthen his party's hand - but Pablo Iglesias, leader of left-wing Podemos, warned that it had only reinforced the far right.
The outcome will require party leaders to be creative, negotiate seriously this time and, for some, swallow their pride, after higher abstention rates on Sunday showed that voters are tired of being called repeatedly to the ballot box.
104/214
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