Exiled former Catalan president Carles Puigdemont, arrested in Italy at Spain's request over an independence referendum that Madrid ruled illegal, was released from prison Friday with no apparent restrictions on his liberty.

Puigdemont, a member of the European Parliament who fled Spain following the 2017 vote, walked out of jail in the Sardinian town of Sassari to cheers from supporters outside.

The 58-year-old separatist leader, who spent the night behind bars after being taken into custody Thursday, was free to leave the island but would return for a hearing in October, his lawyer said.

"We always thought this could happen, but we also knew how it could end," a newly-liberated Puigdemont told the crowds.

"What happens is that Spain never misses an opportunity to make a fool of itself," he said.

The court in Sassari will examine an extradition request for Puigdemont on October 4, his lawyer Agostinangelo Marras said.

Marras insists there is no basis for either the arrest or extradition of Puigdemont, who has been based in Brussels in recent years.

Spanish Prime Minister Pedro Sanchez said Friday he would respect the Italian system but added: "It's clear that Carles Puigdemont must be brought to justice and stand trial."