Around 1,000 demonstrators wearing the Catalan flag as a cape marched through the center of Barcelona on Thursday chanting: "Occupation forces out!".
"We are here to defend Catalan institutions," an 18-year-old demonstrator named Pol Moratalla told AFP. "All we have achieved is all this repression," said Paula Sanchez, a 15-year-old student.
On October 1, Catalan officials held an independence referendum which was deemed unlawful by the central government.
Spain’s Prime Minister Mariano Rajoy has decided to strip Catalan leader Carles Puigdemont and his executive of their jobs. His administration also plans to take control of Catalonia's police force, public broadcaster and parliament.
Spain's senate is poised on Friday to approve measures to seize Catalonia's regional institutions and finances. The measures would remain in place for up to six months, until regional elections are called and a new Catalan parliament is sworn in.
The independence movement in the region argues that Catalonia has an identity distinct from Spain, granting its people the moral, cultural, economic and political right to self-determination.
Independence seekers say they are frustrated that the rich region of Catalonia with its 7.5 million population has long contributed more to Spain than it has received in return from Madrid.