Exiled Catalan separatist leader Carles Puigdemont, who has became a potential kingmaker after Spain's inconclusive parliamentary election, has demanded guarantees before offering support to the country's next government.

"We have no confidence in Spanish political parties," wrote the Catalan separatist on X, the social media platform formerly known as Twitter.

"We cannot move forward on the basis of promises made by those who always fail to keep them, so we need to see solid guarantees before committing to vote."

His comments came a day before Spain's new parliament comes together again amid deep political uncertainty. 

Neither the right nor the left won enough seats to form a working majority, creating a political deadlock that could drag the country back to the polls later this year.

Puigdemont, 60, fled Spain for Belgium to avoid prosecution over his role in a thwarted Catalan independence bid, but continues to head the Catalan separatist party JxCat, which won seven seats in the new Spanish parliament.

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JxCat is still pushing for outright independence from Spain in defiance of past administrations in Madrid, but the seats it won to the national parliament could determine the direction of Spain's next government.

The Catalan separatists have asked for amnesty for anyone pursued by the Spanish justice system over their failed 2017 independence bid and a referendum on self-determination.

Political deadlock

On Thursday, 350 newly elected lawmakers will renew the leadership of the Spanish parliament by voting in a new speaker.

That vote is widely seen as a trial run ahead of next month's crucial investiture vote, which determines who forms the government. 

Neither the left nor the right won the 176 seats needed to have a working majority: each side won only 171.

That is what has put Puigdemont's JxCat in such an influential position.

Of the two main political blocs, incumbent Socialist Prime Minister Pedro Sanchez looks more likely to win their support.

He pledged Wednesday to promote the use of Catalan, Basque and Galician within Europe, a long-running demand of separatist parties.

"Spain speaks Castilian Spanish but also Catalan, Basque and Galician," Sanchez told a gathering of newly elected Socialist lawmakers.

"We are going to promote the use (of these languages) within EU institutions in a commitment I will carry out during Spain's presidency of the European Union," he said of the role Spain took over on July 1.

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