In June, Mr. Sánchez issued pardons to the nine independence activists who had been given lengthy sentences for sedition. But Spain says it can’t offer any pardon to Mr. Puigdemont until he stands trial.
The separatist conflict continues to be one of the most divisive political issues in Spain.
In 2017, when Mr. Puigdemont was regional leader, Catalonia’s government staged an independence referendum in defiance of Spain’s government and its courts, which had declared the vote illegal. Police officers confiscated ballots and even beat people who attempted to vote.
After the central government took control of the region, and as it became clear that sedition charges were in the offing, Mr. Puigdemont fled Spain and was declared a fugitive.
The arrest was welcome news to conservative politicians in Spain, who applauded the move on Thursday night.
“Puigdemont must be tried in Spain for his strike against constitutional legality, and Sánchez must commit to respecting the judgment of justice without pardons,” said Pablo Casado, the head of the conservative Popular Party.
Spain has repeatedly failed in its attempts to extradite Mr. Puigdemont, both from Belgium where he has resided since late 2017, and also Germany, where he was briefly detained in 2018. A German court ordered his release after turning down Spain’s extradition request
La Nuova Sardegna, a local Sardinia newspaper, had reported on Wednesday that Mr. Puigdemont would be a surprise guest at the folk festival in Alghero, a city with deep Catalan roots.