Catalan authorities will not follow orders from the Spanish government if Madrid moves to reassert control over the region, a senior official says.
A regional government spokesman told the BBC that the central government was acting against the will of Catalans.
Spanish Prime Minister Mariano Rajoy has announced plans to sack the region’s government and curtail some of the powers of its parliament.
The Catalan parliament will meet on Thursday to decide on its response.
The pro-independence leaders could decide to formalise a unilateral declaration of independence, the BBC’s Bethany Bell in Barcelona reports.
The Spanish Senate is expected to approve the government’s measures on Friday along with a proposal for fresh regional elections.
On Saturday, Mr Rajoy said he was triggering Article 155 of the constitution – an unprecedented move – which allows for direct rule to be imposed in a crisis on any of the country’s autonomous regions.
But Catalan leaders say they will not accept the plan.
Speaking to BBC Radio 4’s Today programme, foreign affairs spokesman Raul Romeva said: “How can the European Union live with that situation [if this happens]?
“Because what I can tell you is that the people and the institutions in Catalonia will not let this happen.”
He said the Spanish government needed to recognise that the people of the region had voted for independence.
Mr Rajoy insisted the measures would not mean Catalan self-government itself was being suspended and that they were intended to remove the people who had taken illegal action.