Spain's government said Thursday that Prime Minister Mariano Rajoy would hold a special Cabinet meeting over the weekend to trigger the process to take some or full control of Catalonia's semi-autonomous powers.

It was Madrid's response to a letter from Catalan president Carles Puigdemont earlier Thursday, threatening to explicitly declare independence from Spain if no talks were offered by the federal government to negotiate greater autonomy for the region.

Puigdemont said in the letter that if Spain's government continued to "impede dialogue and continues its repression," Catalonia's parliament would proceed to hold a vote on declaring independence from Spain.

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Spain replied that the government would hold the special Cabinet meeting on Saturday and "approve the measures that will be sent to the Senate to protect the general interest of all Spaniards."

The measure falls under Article 155 of Spain's 1978 Constitution, but has never been used in the four decades since democracy was restored at the end of Gen. Francisco Franco's dictatorship.

Puigdemont's letter to Spain's leader arrived minutes before the expiration of a deadline to back down on the independence bid, which was put in motion following a referendum on secession early in October which Madrid has dismissed as illegal.

Puigdemont, in an address to the regional parliament last week, declared independence but then immediately suspended it and challenged Spain to hold negotiations.