Catalonia’s regional parliament has passed a motion to establish an independent Catalan Republic, prompting Spain’s Senate to authorise the central government to take control of the region.
Catalan legislators voted to secede from Spain after an acrimonious debate that saw opposition legislators walk out in protest before the vote.
A majority of senators then gave prime minister Mariano Rajoy the go-ahead to apply unprecedented measures including sacking Catalan President Carles Puigdemont and his cabinet.
It also authorised him to curtail Catalan parliamentary powers.
Mr Rajoy immediately called for calm, tweeting: “I call on all Spaniards to remain calm. The rule of law will restore legality to Catalonia.”
Mr Puigdemont called on fellow separatists to remain peaceful ahead of an expected crackdown by Spanish authorities.
Addressing a crowd of hundreds of supporters packing Catalonia’s parliament building, he said: “In the days ahead we must keep to our values of pacifism and dignity. It’s in our, in your hands to build the republic.
“Today the Parliament fulfilled the long-desired and fought-for step and culminated the mandate of the ballot boxes.”
Those gathered then erupted into the Catalan anthem Els Segadors (The Reapers) and chants of “Liberty!”
European Council president Donald Tusk said “nothing changes” for the European Union after Catalonia’s parliament voted to declare independence, adding that Spain “remains our only interlocutor”.
Mr Tusk wrote on Twitter: “I hope the Spanish government favours force of argument, not argument of force.”
The independence bid has failed to attract support from governments in Europe.