Barcelona braced for more unrest on Thursday, following overnight clashes between Catalan separatists and Spanish police.

Tensions are running high as the central government steps up its efforts to stop an independence referendum scheduled for October 1.

Mass demonstrations on Wednesday ended with police charging against protesters.

Tens of thousands of people had gathered outside the regional government’s offices after Spanish police raided the building and arrested more than a dozen local officials, including Catalonia’s junior economy minister
Josep Maria Jove.

Waving the red-and-yellow Catalan flag, they chanted “Occupying forces out” and “Where is Europe?”.

Spanish authorities say the Catalan referendum is illegal, and they have been trying to stop it by seizing voting material — from ballot boxes to campaign literature and instruction manuals for manning voting stations.

Separatist leader Jordi Sanchez told protesters to prepare for a sustained insurrection.

His Catalan National Assembly has called for a permanent demonstration from noon Thursday.

Ha arribat el moment. Resistim pacíficament. Sortim a defensar des de la no-violència les nostres institucions. Rbla. Catalunya-Gran Via.— Jordi Sànchez (@jordisanchezp) September 20, 2017

The FC Barcelona soccer club said in a statement: “FC Barcelona, in remaining faithful to its historic commitment to the defense of the nation, to democracy, to freedom of speech, and to self-determination, condemns any act that may impede the free exercise of these rights.”

pic.twitter.com/j8hNbQb94a— FC Barcelona (@FCBarcelona) September 20, 2017