Two leaders of Catalonia's pro-independence movement have been jailed by a Spanish judge as authorities probe possible charges of sedition.
Jordi Sanchez of the Catalan National Assembly and Jordi Cuixart of the Omnium Cultural group, both key players in the region’s push for independence, were jailed on Monday.
Catalan police chief Major Josep Lluis Trapero and colleague Lieutenant Teresa Laplana were also questioned and released on condition they surrender their passports.
The National Court in Madrid is investigating the actions of all four during rallies held in Barcelona on September 20-21 ahead of the October 1 referendum.
In response, the Catalan National Assembly and Omnium Cultural have called Catalans to stop work at midday on Tuesday to protest the incarcerations.
Both groups have been pivotal to the independence movement, organising demonstrations in support of secession.