Catalan separatists launched their so-called roadmap for independence on Tuesday, offering a declaration in the regional parliament to split Catalonia from Spain, which Prime Minister Mariano Rajoy has vowed to block.
The local assembly is expected to approve the declaration by Nov. 9. According to the secessionist plan, it will be followed by a constituent process that will lead to full independence within 18 months,
Spain's constitution does not allow any region to break away, so the prospect remains highly hypothetical.
In a short televised statement, Rajoy said he and his government would ensure the declaration has no effect.
"The state may use any available judicial and political mechanism contained in the constitution and in the laws to defend the sovereignty of the Spanish people and of the general interest of Spain," Rajoy said. "Those who want to divide and split Catalonia from Spain must know that they will not succeed."
Pro-independence parties last month won a majority of seats in Catalonia's parliament. That election set the region on a collision course with Spain's central government over independence, less than two months before a general election.
(Reporting by Julien Toyer)