European MEP and former Catalan president Carles Puigdemont -- in exile in Belgium since 2017 after an attempt by the region to gain independence through a referendum that Spain ruled was unconstitutional -- was arrested in Italy on Thursday, his lawyer said.
The European MEP was expected to appear in court on Friday at a hearing that could see him extradited to Spain to face sedition charges.
The Catalan leader -- who has been based in Belgium since the 2017 referendum -- was detained in Alghero, Sardinia, his chief of staff, Josep Lluis Alay, wrote on Twitter.
"At his arrival at Alghero airport, he was arrested by Italian police. Tomorrow (Friday), he'll appear before the judges of the court of appeal of Sassari, who will decide whether to let him go or extradite him," Alay said.
Puigdemont's lawyer, Gonzalo Boye, tweeted that the exiled separatist leader was arrested on his arrival in Italy, where he was travelling in his capacity as an MEP.
He said the arrest was made on the basis of a warrant issued in October 2019 that had since been suspended.
Puigdemont, 58, is wanted in Spain on allegations of sedition over his attempts to have the Catalan region break away from Madrid through the 2017 referendum.
His arrest comes a week after the left-leaning Spanish government and regional Catalan authorities resumed negotiations to find a solution to Spain's worst political crisis in decades.
In March, the European Parliament rescinded immunity for Puigdemont and two other pro-independent MEPs, a decision that was upheld in July by the EU's General Court.
However, the European Parliament's decision is under appeal and a final ruling by the EU court has yet to be made.
Following Thursday's arrest, Madrid expressed "its respect for the decisions of the Italian authorities and courts".
"The arrest of Mr Puigdemont corresponds to an ongoing judicial procedure that applies to any EU citizen who has to answer to the courts," the Spanish government said in a statement.
The statement added Puigdemont should "submit to the action of justice like any other citizen".