More than 500,000 people gathered in downtown Barcelona on Friday in a show of force after the Supreme Court handed down stiff prison sentences to nine separatist leaders who led a failed independence bid in 2017.
Demonstrators waving Spanish flags filled the Plaza de Colon in the city centre in the largest protest Sanchez has faced, with their slogan "For a united Spain, elections now!" a reminder of the pressure on his minority government.
Puigdemont said he will continue to travel around Europe in an attempt to explain the separatist position in wealthy Catalonia, which has so far failed to garner any support from European governments or major political parties.
That could take up to two months if no candidate gets an absolute majority of votes. If parties agree on a regional leader and it's Puigdemont while he is still abroad, Madrid would declare the vote null and keep its control over the region.