A day after the central government dismissed the Catalan president, his deputy, ministers and parliament, Madrid on Saturday sacked the chief of police in Catalonia as it moved to seize direct control of the northeastern region.
The move came a day after the Catalan regional parliament declared independence, sending shockwaves across Europe.
Moving to quash what he termed an "escalation of disobedience", Prime Minister Mariano Rajoy called December 21 elections in the region under sweeping powers granted by the Senate in response to Catalan lawmakers voting to declare an independent republic.
The dismissal of Josep Lluis Trapero, seen as an ally of his region's separatist leaders, was announced in Saturday's official government gazette.
In an effort to defuse tensions, the regional police force urged its members to behave in a neutral manner and not to take sides, an internal note seen on Saturday by Reuters showed.
Trapero became a hero to the secessionists after his force took a much softer stance than national police in enforcing a government ban on an independence referendum on October 1.
Madrid accuses Trapero of disobeying court orders to block the banned vote.
Instead, the ballot was disrupted, violently in some cases, by officers from Spain's national police and Guardia Civil paramilitary forces.
“Given that there is it is likely to be an increase in gatherings and rallies of citizens in all the territory and that there are people of different thoughts, we must remember that it is our responsibility to guarantee the security of all and help these to take place without incident,” the memo said.
Trapero’s dismissal was signed off by Spanish Interior Minister Juan Ignacio Zoido.
Spain’s High Court last week banned Trapero from leaving Spain and seized his passport as part of an investigation for alleged sedition, although it did not order his arrest.
All eyes this weekend will be on whether Catalonia's separatist executive, led by Carles Puigdemont, will willingly step aside for caretaker envoys from Madrid.
Spain's Deputy Prime Minister Soraya Saenz de Santamaria is due to meet later with secretaries of state who will likely take charge of Catalonia's regional ministries.
Tens of thousands celebrated in Barcelona and other Catalan cities after Friday's independence declaration, which analysts say the region has no legal power to execute.
But anti-secession rallies have been called for the capital, Madrid, on Saturday, and for Barcelona on Sunday.
The move to quash Catalan powers under Article 155 of the Spanish constitution is likely to anger many in a region of some 7.5 million people that enjoyed considerable autonomy, with control over education, healthcare and police.
It is the first time the central government has curtailed autonomy in the region since dictator Francisco Franco's repressive 1939-75 rule.
Independence supporters have warned they will resist the temporary measure, implemented under a constitutional article devised to rein in rebel regions.
"We won't cave in to Rajoy's authoritarianism nor to 155," the far-left CUP party, an ally of Puigdemont, tweeted on Friday.
The Spanish government has received unwavering support from the United States and its allies in the European Union.
The bloc is increasingly wary of nationalistic and secessionist sentiment, particularly after Britain's dramatic decision last year to leave the bloc.
EU President Donald Tusk insisted Madrid "remains our only interlocutor" in Spain, but urged it to exercise restraint.
"I hope the Spanish government favors force of argument, not argument of force," he tweeted.