Catalonia's regional parliament has passed a motion saying it will establish an independent Catalan Republic.
Separatist legislators erupted in applause as the vote was approved with 70 votes in favour, 10 against and two blank ballots.
Most opposition members had left the chamber in protest moments before the vote.
Spain opposes the independence bid and the national government in Madrid is readying measures to take over control of the north-eastern region. No country has expressed support for the secession bid.
The motion calls for beginning an independence process that includes drafting Catalonia's new top laws and opening negotiations "on equal footing" with Spanish authorities to establish co-operation.