Spanish Prime Minister Mariano Rajoy said Thursday that the Catalan government's decision to call an independence referendum for the region was an "intolerable act of disobedience" against the country's democratic institutions.

He said his government was asking Spain's Constitutional Court to annul the law voted by Catalonia's parliament on Wednesday, which cleared the way for an October 1 vote, and said all municipalities in the region would be warned over their "obligation to impede or paralyse" efforts to carry out the vote.