German prosecutors on Tuesday asked a court to order the extradition to Spain of Catalonia's ousted president Carles Puigdemont on a rebellion charge following his arrest in Germany last month.
The request comes after protests by independence supporters at the weekend in Berlin and Catalonia calling for Puigdemont's immediate release.
"The prosecutor's office of Schleswig-Holstein state applied for an extradition arrest warrant against former Catalonian regional president Carles Puigdemont from the superior regional court," it said in a statement.
It was not immediately clear when the court would rule on Puigdemont's possible extradition.
Puigdemont was arrested by German police on March 25 as he was travelling from Finland back to Belgium, where he has been living in self-imposed exile since Catalonia's failed independence bid last October.
The detention came two days after a Spanish judge issued European arrest warrants for Puigdemont and other fugitive separatist leaders.
They have been ordered to stand trial for rebellion, misuse of public funds and disobeying the state for organising last year's referendum on Catalan independence, which Madrid deemed illegal.
Puigdemont's arrest has sent tensions soaring at home, triggering a wave of protests in the wealthy northeastern Spanish region.
German judges have ordered Puigdemont to remain in custody in the northern town of Neumuenster as they mull Spain's request for him to be handed over.
They have 60 days to make a decision.
German media say the request has been complicated by the fact that rebellion, which carries a maximum penalty of 30 years in jail in Spain, is not a crime under German law.
However the prosecutor's office said that "after intensive review" it concluded that the rebellion charge "contains in essence the accusation of calling an unconstitutional referendum despite violent riots that could be expected," thus matching the German charge of "treason".
"Word-for-word conformance between the German and Spanish criminal codes is thus not legally required," it said.
The superior regional court confirmed it had received the request, adding that it was "undetermined when a decision on the application can be expected".
The court must first decide if there is a legal basis to put Puigdemont in pre-extradition custody by reviewing the written request from Spain. It will then rule on the extradition bid itself.
He can appeal an order of extradition to a German federal court, a course his lawyers have said they will pursue.
Puigdemont has already filed an appeal in Spain against a decision to prosecute him, arguing the rebellion charge against him is not justified.
The 85-page appeal, seen by AFP on Monday, asks that the Spanish Supreme Court's "actions" be declared "null" 10 days after Judge Pablo Llarena said 25 Catalan separatist leaders -- including Puigdemont -- would be prosecuted over the region's secession bid.
In the appeal, Puigdemont's lawyer Jaume Alonso-Cuevillas demands that the court drop the charges of rebellion and misuse of public funds against Puigdemont and another of his clients -- former regional minister Clara Ponsati.
Both fled Spain for Belgium after the failed independence push. Ponsati then left for Scotland where she was detained after Spain issued European arrest warrants against fugitive separatist leaders, and freed on bail.
Alonso-Cuevillas also wants the court to drop charges of misuse of public funds and disobedience against another client, former regional minister Lluis Puig.
The appeal states that under Spanish law, the rebellion offence, which can carry up to 30 years in prison, implies there was a violent uprising.
But it maintains that if there was any violence before or on October 1, the day when an independence referendum was held in Catalonia despite a court ban, it was "isolated" and did not justify the rebellion offence.