Political parties in Catalonia have started campaigning for the early regional election called by the Spanish government in hopes of quashing the region's independence movement and featuring candidates who are either in jail or living abroad to avoid detention.
The highly polarised parliamentary election set for December 21 is shaping up as a plebiscite between Catalans who support secession and those who favour remaining in Spain. Voters are choosing regional lawmakers and top government officials to replace the ones the central government removed from office in late October.
Hours before pro-secession parties held evening rallies to launch their bids for seats in the Catalan parliament, a Supreme Court judge in Madrid ruled that four prominent members of the region's independence movement must remain jailed without bail.
They include former regional Vice President Oriol Junqueras, who is heading up the slate of the left-republican ERC party in the upcoming election. Junqueras was unseated along with ex-president Carles Puigdemont and the rest of Puigdemont's Cabinet after regional lawmakers passed a declaration of independence that Spanish authorities deemed illegal.
Six other Catalan politicians who had been jailed with Junqueras since early November were released from jails near Madrid late Monday after the 100,000-euro ($A150,000) bail a Supreme Court judge set for them earlier in the day was posted.
Thousands of Catalan separatists rallied in town squares across the northeastern Spanish region to demand the release of the four remaining leaders still in prison.
Several protesters held up signs saying "Freedom for Political Prisoners."