Lawmakers in Catalonia on Monday approved a plan that put the autonomous region on a course toward independence, a move the central government in Madrid says violates the constitution and which Spanish Prime Minister Manuel Rajoy pledged to undo.

The regional parliament in Barcelona voted 72 to 63 to pass a resolution declaring "the start of a process toward the creation of an independent Catalan state in the form of a republic," as well as a "process of democratic disconnection not subject to the decisions by the institutions of the Spanish state," The Associated Press reported.

The proposal was introduced by the "Together for Yes" alliance and the extreme left-wing Popular Unity Candidacy, which had obtained a parliamentary majority in regional elections in September. Raul Romeva, who leads "Together for Yes" alliance, explained Catalonia's separatist ambitions at the start of the session.

"There is a growing cry for Catalonia to not merely be a country, but to be a state with everything that means," he said. "Today we don't only open a new parliament, this marks a before and after."

Catalan branches of Spain's ruling conservative Popular Party, as well as the opposition Socialist Party, had attempted to prevent Monday's vote before it even took place, but the country's Constitutional Court ruled last Thursday that it could go ahead.

In a nationally televised address, Rajoy, meanwhile, said his government was already working towards again appealing the legislation to the high court, the Guardian reported.

"I've said it continuously and I reiterate it today -- the government will not allow this to continue," the prime minister said. "Catalonia will not disconnect itself from anywhere, and there will be no fracture."

During a visit to the western city of Béjar, Rajoy further said Madrid intends to use "all means" to rein in Catalonia's secessionist moves, the Spanish newspaper ABC reported.