Carles Puigdemont, the Catalan separatist leader, was arrested on Thursday in Sardinia after fleeing Spain some four years ago.
The former president of the Generalitat was arrested by officers at Alghero airport, where he spent the night in the police station, before being released on Friday by a local court.
He will have to remain on the island, however, until a decision has been made about his possible extradition to Spain.
The separatist leader had travelled to the Italian island to meet with Sardinian breakaway leaders.
Puigdemont was arrested by two plainclothes police officers under a European search and arrest warrant issued by Spain’s Supreme Court. His lawyer, Gonzalo Boye, confirmed the arrest.
The current head of the Generalitat, Pere Aragonès, who has called an emergency meeting this Friday, condemned the arrest and expressed his support: "We are by your side, President Puigdemont."
Puigdemont has been hiding out in Belgium since October 2017, when he escaped arrest by the Spanish authorities for his role in the illegal Catalan independence referendum earlier that month. Since then he has successfully fought off Spain's attempts to have him extradited.
In his absence from Catalonia Puigdemont was elected as an MEP in 2019. But, back in July, the Court of Justice of the European Union stripped the former Catalan president and separatist leader of his immunity as a member of the European Parliament.
This is the second arrest of Puigdemont since he fled to Brussels, hidden in the boot of a car, on 30 October, 2017, days after the unilateral declaration of independence was approved in the Catalan Parliament.
He was arrested on 25 March, 2018, under a European extradition order issued by the Supreme Court. Puigdemont spent twelve days in jail until the Higher Regional Court of Schleswig-Holstein, in northern Germany, allowed his release on bail of 75,000 euros and declared that the crime of rebellion against him by the Spanish courts was not admissible.