Pep Guardiola says the decision to imprison Catalan politicians is "scary" as the crisis in the Manchester City manager's home region continues.
Nine ex-minsters from the dissolved Catalan parliament appeared at Spain's high court on Thursday accused of rebellion, sedition and misuse of public funds.
All, with exception of bailed former Business Minister Santi Vila were detained, while ousted Catalan leader Carles Puigdemont remains in Belgium and was one of five separatist politicians not to answer the summons in Madrid.
Spanish Prime Minster Mariano Rajoy imposed direct rule upon Catalonia last week after lawmakers in the region voted to declare independence on the back of the October 1 referendum that was deemed illegal by Spain's national government.
Guardiola has regularly spoken out in favour of Catalans being allowed a vote on self-determination and lamented the imprisonment of pro-independence politicians Jordi Sanchez and Jordi Cuixart last month.
At a news conference ahead of City's Premier League match against Arsenal on Sunday, he again refused to shy away from situation he believes is worrying and shows democracy in Spain to be going backwards.
"I wish that the politicians who they have put in prison are released soon," he said.
"I'm worried because what happened to them could happen to us for giving an opinion, it could happen to anyone.
"The two Jordis leading the Catalan organisation were put in prison for asking to vote in a legal referendum.
"I think the Spanish government and the Catalan government should sit and talk and try to agree a referendum for both sides.
"Until then it's a really difficult situation to be solved. These politicians are in prison for fulfilling the electoral programme. They were fulfilling the wish of the Catalan people.
"Now them and their families are suffering this situation. It can happen to other people, to all of us, just for wanting to vote. That was the main desire of the Catalan people.
"It's a little bit scary - we are going backwards in a democratic state, that we have regressed so much in the rule of law."
Mr Rajoy called local elections for December 21 in Catalonia following his decision to dissolve the regional parliament.
Guardiola added: "I just wish that the situation can be resolved soon and these guys can be released and December 21 that there is an election in Catalonia – a fair election where the people can express their wish with freedom.
"[The election must ] recover the institutions and [make sure] that the Parliament of Catalonia is again what it was."
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