Thousands of Catalan separatists are marching in Barcelona to proclaim the innocence of 12 of their leaders who are on trial for their role in a failed 2017 secession bid.

The front line of marchers on Saturday held a long banner saying in Catalan “self-determination is not a crime.” It was followed by many people carrying pro-independence flags.

The trial of the 12 high-profile separatists started this week in Spain’s Supreme Court in Madrid. They are facing charges for having ignored a court ban on holding a secession referendum and for issuing a declaration of independence that received no international recognition in October 2017.

Separatists claim that Catalonia has a right to self-determination. Spain’s government says any vote on independence would require the national Parliament to amend the Constitution.

A man walks at Colon square in Madrid, Spain, Friday, Feb. 15, 2019. The prime minister of Spain has called early general elections for late April, the third such ballot in less than four years in an increasingly fragmented partisan landscape and with Catalonia's independence push dominating the political debate. (AP Photo/Andrea Comas)
A man walks at Colon square in Madrid, Spain, Friday, Feb. 15, 2019. The prime minister of Spain has called early general elections for late April, the third such ballot in less than four years in an increasingly fragmented partisan landscape and with Catalonia’s independence push dominating the political debate. (AP Photo/Andrea Comas)