The leader of the Spanish Socialist Party says it won't support Prime Minister Mariano Rajoy's second attempt in six months to form a government.

Pedro Sanchez said Saturday his party "will vote no" to Rajoy's bid following Spain's repeat election on June 26.

Rajoy's ruling Popular Party won that vote and the victory margin was noticeably wider than in the earlier vote in December, but the party still failed to achieve an absolute majority in Parliament.

The repeat election was called after the parties failed to form a coalition government following the first vote. Rajoy has since attempted to form a coalition government with the Socialist Party, which ended second in the repeat election. The new left-wing alliance Unidos Podemos was third and the conservative Ciudadanos fourth.