Catalan leader Carles Puigdemont on Tuesday proclaimed the region's independence from Spain but said its effects would be suspended to allow for talks with the Madrid government.
"I assume the mandate that Catalonia should become an independent state in the form of a republic ... I propose suspending the effects of the declaration of independence to undertake talks to reach an agreed solution," Puigdemont told the regional parliament in Barcelona.
Though Puigdemont stopped short of seeking the explicit support of the chamber for the declaration of independence in a vote, a move that would have closed the door to any negotiated solution, the declaration plunges Spain into the unknown.
The Spanish government has said any unilateral declaration of independence would be illegal and has promised action "to restore law and democracy" if the parliament of the autonomous and affluent northeastern region presses ahead.
Prime Minister Mariano Rajoy could take the unprecedented step of dissolving the Catalan parliament and triggering new regional elections, the so-called "nuclear option".
The Madrid government could also ask the courts to strike down a declaration of independence as unconstitutional.
Despite renewed calls for dialogue with Madrid, the proclamation makes a negotiated solution more difficult as Rajoy has said he would not talk to the Catalan leaders until they drop plans for independence.