Thousands of people have turned out in Barcelona to show their support for acting Catalan president Artur Mas.
He has gone before a court in the city to testify over a referendum on independence from Spain, which went ahead last November despite being ruled illegal.
Supporters draped with the Catalan red and yellow striped flag chanted “president” and “independence” as Mas walked in and out of the Supreme Court of Catalonia.
Mas was indicted last month on preliminary charges of disobedience, abuse of authority and usurping authority.
In court, he reportedly said the referendum was a core objective of his administration and he assumed total responsibility for holding it.
Spain’s Prime Minister Mariano Rajoy has rejected calls for a poll on independence, arguing that such a vote would be against the constitution. He argues one part of Spain cannot decide what happens to the whole.
Secessionist parties secured an absolute majority in Catalonia’s regional parliament in a local election held last month.
Parties favouring independence are still in talks over the formation of the government, with reluctance from the extreme left separatist party CUP to support Mas.
Opinion polls show that a majority of Catalans would like to remain within Spain, if the region were offered a more favourable tax regime and laws that protect its language and culture.