Carles Puigdemont has been living in exile in Belgium since 2017, accused by Spain of, among other things, rebellion and incitement in connection with Catalonia's independence attempt four years ago.

An arrest warrant has been issued and last spring he lost his immunity from prosecution as a Member of the European Parliament, following a vote in the European Parliament.

On Friday, a court will decide whether Puigdemont should be released or extradited to Spain, his chief of staff Josep Lluís Alay said on Twitter.

"On arrival at the airport in Alghero, he was arrested by Italian border police.

Tomorrow (Friday) he will be brought before the court in Sassari, "he writes.

Nine other separatist leaders were pardoned

In June, Spanish Prime Minister Pedro Sánchez pardoned nine other Catalan separatist leaders who in 2019 were sentenced to 9-13 years in prison for inciting and abusing public funds in connection with the Catalan independence attempt.

Spain also has arrest warrants issued for former Catalan regional ministers Toni Comín and Clara Ponsatí.

Like Puigdemont, they now sit in the European Parliament and, like him, lost their immunity from prosecution this spring, when the allegations formally date from before the three Catalans were elected to the European Parliament.