Pro-independence protesters are blocking major motorways, train lines and avenues across Catalonia, one year after a banned referendum was crushed by Spanish police.
Monday's protests have been called on online messaging apps by the Committees for the Defence of the Republic - local activist groups that emerged after the unauthorised vote on 1 October 2017.
In Girona, north of Barcelona, hundreds of activists occupied the high-speed railway tracks, while regional police tried to stop more protesters from entering the area of the station.
Local media also reported road blockages on the AP-7 highway, the main artery along eastern Catalonia leading to the French border, and in central streets of the cities of Lleida and Barcelona, the regional capital.
On Sunday, 14 people were injured and six arrested after police clashed with Catalan separatists in downtown Barcelona. At least one regional police officer was also injured in the riot, according to Catalan authorities.
Violence erupted after separatists protested at a march of around 3,000 people, which was being held to demand Spain’s nationwide police officers were paid as much as Catalan’s regional police.
The clashes come after a poll in late September showed only 15 per cent of Spaniards consider the political situation in Catalonia to have improved, while 69 per cent believe it has worsened.
Polls in Catalonia reveal an ongoing stalemate, with no clear majority either in favour or against remaining in Spain.
Yet while nationalist parties squabble to the point where the regional parliament was suspended for 70 days this summer because of their infighting, the Republican movement has shown no sign of losing its power to mobilise its grassroots supporters.
On Monday morning, Catalonia's regional government returned to a school in northern Catalonia where police stormed in a year ago to bar people - including Catalan president Carles Puigdemont - from voting in the referendum.
The incident left hundreds injured in front of cameras broadcasting the images around the world.
Mr Puigdemont, who ended up voting in another polling station, is now sought in Spain under preliminary charges of rebellion. He has so far fought off extradition to Spain from both Germany and Belgium.
Additional reporting by AP
