Spain's acting Prime Minister Pedro Sanchez embarked on a flurry of phone calls with rival party leaders today to try to break a political stalemate and avoid the fourth national election in as many years.
However a source close to the talks cast doubt on the chance of a breakthrough.
The euro zone's fourth-largest economy has been in political limbo since an inconclusive election in April in which Sanchez' Socialist Party won most seats but failed to secure a majority, with reforms being put on the back burner.
But as the election deadline neared - if parliament does not confirm Sanchez as prime minister by next Monday, Spain will hold another parliamentary poll in November - the political manoeuvring stepped up a gear.
Sanchez was calling center-right Ciudadanos leader Albert Rivera, Unidas Podemos' Pablo Iglesias and People's Party's Pablo Casado throughout the morning to learn if they could back his bid to be confirmed as premier, a Socialist source said.
"Pedro Sanchez's ambition is to start the legislature without having to go to elections," the source said.
However party leaders have spent more time publicly blaming each other for the impasse than negotiating in recent months, and the source close to the talks cast doubt on the chances of a deal in the latest discussions.
"It's meant to show that they tried until the end," the source said.
Iglesias told Sanchez in their phone call that he had not changed his position, and that if Sanchez did not agree to a fully fledged coalition he would not back him, Socialist and Podemos party sources said.
Sanchez has been saying for months that Podemos would be his preferred partner, but has rejected the idea of such a coalition.
Meanwhile, Casado reiterated his opposition to backing Sanchez as premier, a Socialist source said.
Earlier today, Rivera said he wanted to meet Sanchez, after having made a conditional offer to support the acting premier. However a Socialist lawmaker later said the two men would not meet today, casting further doubt of any chance of a deal.
Aware of voters' weariness with repeated elections, Spanish political leaders have been trying to deflect any blame for a possible new poll and it was unclear if this week's developments could be a game-changer or were pre-election positioning.
All the main party leaders are meeting with King Felipe later today and are expected to tell him if they would back Sanchez's bid to become premier.
Today was expected to be the day when Spanish voters would know if there would be new elections, but if a meeting between Sanchez and Rivera is indeed planned, the leaders could ask the king for more time before a final decision, ahead of the Monday's ultimate deadline.
If it all goes down to the wire and Sanchez decides to seek an investiture vote, the last day for parliament to start an investiture debate is Friday, with a first vote on Saturday and a second vote on Monday, a parliament official said.
Spain's economy has been so far largely unaffected by the political stalemate and is seen growing more than euro zone average.