Seven of the imprisoned politicians are candidates with separatist parties.
Pilar Gonzalez, 76, said while walking her dog in Barcelona that the jailed Catalan political leaders were "political prisoners".
While the separatists are united against what they say is "repression" from Madrid, they are divided over the future of their region. "We have it in our hands to end the independence movement and start a new era for Catalonia". Four male colleagues left the Estremera prison, some 50 kilometers Southeast of Madrid, in the evening.
Voters are choosing regional representatives and top government officials to replace those removed by the national government in late October.
A Spanish judge has ordered that four prominent members of the Catalan independence movement should remain in custody, including the vice-president of the ousted regional government.
They include former regional Vice President Oriol Junqueras, who heads the slate of the left-republican ERC (Republican Left of Catalonia) party. They have since called to be released to campaign for the election.
But Marta Rovira, Junqueras's deputy in his ERC party, said the decision was politically motivated.
The Spanish government has said the early election is an attempt to find a democratic way out of the nation's worst crisis in almost four decades.
The three held a narrow majority of 72 out of the 135 seats until the chamber was dissolved last month.
Ban on Russian anti-virus software in government
Ciaran Martin, the centre's chief executive, said: "The NCSC advises that Russian Federation is a highly capable cyberthreat actor which uses cyber as a tool of statecraft".
But the vote is shaping up as a plebiscite between those for and against independence, with polls predicting a close race between the two camps.
The CIS survey said the poll had a margin of error of two percentage points. It said 3,000 people were quizzed via telephone calls from November 23 to 27.
Spain is seeking to have Puigdemont and four of his former ministers who fled with him sent back to face charges over their role in the independence drive.
Six politicians will be released on bail.
On Monday, Spain's Supreme Court refused bail for Junqueras, Forn and leaders of Catalan civic groups Asamblea Nacional Catalana (ANC) and Omnium Cultural, Jordi Sanchez and Jordi Cuixart.
Rajoy and fellow opponents of Catalan independence have hitched their hopes on a record turnout on December 21 to return a legislature in favor of unity with Spain.
These events took place in the aftermath of an independence referendum held in Catalonia on October 1 that the Spanish authorities declared illegal. All Catalan politicians have faced charges of rebellion and sedition.
Mr Puigdemont's defence lawyer, Paul Bekaert, insisted that the Spanish charges were not punishable in Belgium and thus there were no grounds for extradition.
The remaining ex ministers and former regional president Carles Puigdemont are in Belgium, fighting extradition to Spain.