STRASBOURG, France (Reuters) - Catalan separatist leaders Carles Puigdemont and Antoni Comin took their seats in the European Parliament on Monday, vowing to force their secessionist cause onto Europe’s agenda just days after Spain repeated its call for their arrest.

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The two politicians, both of whom live in self-imposed exile in Belgium, have long been sought by Madrid over their role in defying Spanish courts to hold a 2017 referendum on independence and the short-lived secession declaration that followed.

“This is a historic day for us,” Puigdemont told reporters outside the European Parliament in the French city of Strasbourg, flanked by cheering supporters as he prepared to head into his first parliamentary session.

“We are here to remind people that the Catalan crisis is not an internal matter, it is a European one.”

Puigdemont and Comin were elected as European parliamentarians (MEPs) last May but were unable to return to Spain to take oaths and collect credentials for fear of arrest.

However, their status shifted last month when the Court of Justice of the European Union (CJEU) ruled that another separatist leader Oriol Junqueras, also elected an MEP in May, was entitled to immunity.

Junqueras, who remained in Spain, was sentenced to 13 years’ prison in October over his role in Catalonia’s 2017 breakaway bid.

After Spain’s Supreme Court ruled last week that the sentencing barred him from immunity as an MEP, the European Parliament on Friday revoked his mandate.

Puigdemont called for Junqueras to be allowed to carry out the mandate he had been handed by voters.

“If the European Union was really a union of rights and freedoms, Oriol Junqueras would be here today,” he said.

Spain’s Supreme Court called on Friday for the European Parliament to strip Puigdemont and Comin of their immunity, reiterating that the pair should be handed over to Spanish authorities based on their European arrest warrants.