Protesters were gathering for a fresh round of demonstrations in Barcelona on Tuesday to demand the release of two leaders of Catalonia's pro-independence movement who were jailed in a sedition probe.
A Madrid judge on Monday provisionally jailed Jordi Sanchez and Jordi Cuixart, the leaders of grassroots organisations Catalan National Assembly and Omnium Cultural.
The judge ruled they were the orchestrators of massive demonstrations September 20-21 in Barcelona that hindered a police operation against preparations for the October 1 independence referendum.
Protests have been called at midday today in Barcelona, the Catalan capital, and an evening demonstration is also planned.
Some 500 students left classrooms in one of Barcelona's main universities to join the demonstrations.
"We urge the release of our political prisoners and call on Catalan authorities to revoke the suspension of the independence declaration and proclaim the Catalan republic," said Aina Delgado Morell, a representative of Universitats per la Republica, a pro-independence student organisation.