MADRID — Spain's repeated election Sunday failed to clarify the political future of the European Union's fifth-largest economy, as another inconclusive ballot compelled leaders to resume six months of negotiations on who should form a government.
The conservative Popular Party, which has ruled for the past four years, again collected the most votes in the election but still fell shy of the majority of 176 seats it needs in the 350-seat Parliament to form a government on its own.
With 99.9 percent of the votes counted late Sunday, incumbent prime minister Mariano Rajoy's party had picked up 137 seats in Parliament. That is better than the 123 it won in December but still means it will need allies if it wants to govern. Its earlier efforts to find support from rival parties after December were fruitless.
Even so, Rajoy declared he would make a push for power, telling a victory rally in Madrid, ''We won the election, we demand the right to govern.''
It is unlikely to be as simple as that, however. For the past six months, the main parties have quarreled endlessly over who should assume power. In the end, King Felipe VI had to call another election. A third one, in six months' time, is still a possibility.
Antonio Barroso, a London-based analyst with the Teneo Intelligence political risk consulting group, said he expected tough negotiations among the parties in coming weeks.
''It was hoped that these elections would bring clarity and that a government would be formed quickly, but I don't think that's how it's going to be,'' Barroso said.
Spain has never had a coalition government.
The center-left Socialist Party placed second, collecting 85 seats, according to the count by the country's Interior Ministry. That was five fewer seats than six months ago but the Socialists kept their influence by fending off a challenge from a radical leftist alliance.
''We are the foremost political power on the left,'' Socialist leader Pedro Sanchez told supporters in Madrid.
United We Can — which brings together Podemos, a two-year-old party that grew out of a grass-roots antiausterity protest movement, the communists, and the Greens — was third with 71 seats.
The alliance, headed by pony-tailed political science professor Pablo Iglesias, had hoped to overtake the Socialists and break the country's traditional two-party system. The Popular Party and the Socialists have alternated in power for decades.
''We had expected to do better,'' Iglesias said.
The business-friendly Ciudadanos party came in fourth with 32 seats. Other, smaller parties won the rest of the vote by Spain's roughly 36.5 million voters.
Public anger at high unemployment, cuts in government spending on cherished services such as welfare and education, and unrelenting political corruption scandals shaped the two-week election campaign.
At a Madrid polling station, many voters said they wanted Sunday's election to bring a break with the past.
''I'm voting for change, so that our politicians understand that we don't agree with what they've been doing,'' said Maria Jesus Genovar, a 47-year-old teacher who supported United We Can.
That party wants to improve job security, increase the minimum wage, and strengthen the welfare state and other public services.
But Maria Jose Escos, a 59-year-old government worker, said she had no appetite for the new parties. ''I'd like everything to be like it was before,'' the Socialists supporter said.
Iglesias has said he wants a pact with the Socialists in order to oust Rajoy. But a major sticking point is Iglesias's insistence on letting the powerful northeastern region of Catalonia stage an independence referendum — a possibility other main parties have rejected outright.
Ciudadanos is willing to talk to both the Popular Party and the Socialists but wants no deal with United We Can.
Besides tensions over Catalonia, Spanish politics has been dominated by a national unemployment rate of more than 20 percent and an unrelenting stream of corruption scandals, mostly involving members of the Popular Party and the Socialists.
On Friday, all four main candidates made final pleas to voters after a week dominated by the Britain's decision to leave European Union and leaked recordings that appeared to show a minister asking an official to help him dig up dirt on political rivals.
Rajoy said the People's Party was the only force that could guarantee a stable, moderate government and urged voters to put aside their ideological differences. Iglesias told Spaniards they had a historic chance to replace the failed politics of the past.
The prime minister set out his commitment to reviving the economy, keeping the Catalan independence movement in check, promoting EU integration, and defeating terrorism.
''Vote for the PP because we're the only ones that can win the election and continue this path,'' he said.
Amid a global selloff from the British vote on Friday, Spanish assets took a beating. The extra yield investors demand to hold Spanish 10-year bonds instead of safe-haven German securities jumped 31 basis points to 168 points, the highest in two years, while Spanish stocks slumped 12 percent.
The prime minister has struggled to get his message across in the final days of campaigning.