Spain's central government and regional Catalan authorities were battling at the weekend over control of the regional police force in a dispute seen as central to the fate of the Catalonian independence referendum on October 1.
The Spanish courts have ruled the vote illegal, and the Catalan police force, the Mossos d’Esquadra, is expected to work alongside thousands of state police, brought especially to the region, to prevent it.
The Spanish interior ministry told all local and national police forces on Saturday they had been temporarily placed under a single chain of command reporting directly to the interior ministry in Madrid.
The ministry would directly co-ordinate all police operations in Catalonia as the government prepares to forcibly prevent the referendum.
But the pro-independence Catalan regional government has said it will not comply with the ruling, opening up another front in a rapidly escalating conflict between Madrid and Catalonia that threatens to turn into an acute constitutional crisis.
Spanish state police, acting on court orders, last week raided regional government offices, arrested senior Catalan officials and seized ballot papers, ballot boxes, voting lists and other electoral material.