Authorities in Madrid on Thursday removed a plaque honouring a Civil War-era Republican premier after the far-right Vox party used a loophole in a law meant to tackle Spain's fascist past to convince the city to take it down.
Workers in overalls tore down the plaque from the facade of Francisco Largo Caballero's birthplace on the 115th anniversary of the renowned unionist's birth.
Largo Caballero's statue had already been smeared on Sunday with graffiti saying, "Assassins, Reds - No".
Vox tweeted that the move was a warning to Spain's ruling leftist coalition to withdraw the Historic Memory law passed in 2007 to tackle the legacy of General Francisco Franco's 1939-1975 dictatorship.
"In a democratic country, threats are unacceptable," Socialist Prime Minister Pedro Sanchez tweeted in response. "We will continue building a Spain worthy of those who fought so we could be what we are now: free."
Madrid's leftist Mas Madrid party said it would go to court to challenge the city hall's decision to remove the plaque.
Caballero, the Socialist prime minister in Spain's Second Republic at the start of the 1936-39 civil war, died in exile in Paris in 1946 following his liberation from a German concentration camp. He had fled Spain to France upon Franco's defeat of Republican forces.
In taking down the Caballero plaque, the centre-right majority in Madrid City Hall invoked a clause in the Historic Memory Law allowing public administrations to remove any commemorative objects that exalt leaders or symbols related to the 1930s military coup and the Civil War.
The Socialist-led government aims to reform the law so that it finances the unearthing of mass graves and prevents glorification of Franco's rule, while investigating events which took place during his dictatorship.