BARCELONA (Reuters) - Protesters clashed with police trying to reclaim disputed religious artefacts from a museum in Catalonia on Monday, in the latest display of tension between Catalan separatists and Spain’s central government ahead of a Dec. 21 election.

A monastery in neighboring Aragon region says over 44 of its artefacts were sold illegally to Catalonia in the 1980s and the issue has become a symbol of broader disagreement between opponents and supporters of Catalan independence.

Culture Minister Inigo Mendez de Vigo angered Catalan nationalists in November by using special temporary powers to accept a petition by a judge from Aragon calling for the artefacts to be returned to their previous home, the Monastery of Sijena.

The previous month, Madrid took control of Catalonia to quell the crisis over secession and called a snap regional election.

Hundreds of demonstrators on Monday massed at the museum of Lleida in western Catalonia where the artefacts were kept and pro-independence groups called supporters to stop the police from removing them.

There were minor scuffles, though no injuries were reported and the artefacts were eventually taken away at around noon.

Former Catalan leader Carles Puigdemont, currently in self-imposed exile in Brussels, criticised the move on Twitter and blamed the three principal unionist parties running in upcoming elections, the ruling People’s party (PP), the socialist party and Ciudadanos.

“Carried out at night and using a militarised police force, as always, and taking advantage of a coup d’etat to plunder Catalonia with complete impunity: This is the model that Ciudadanos, PSC and PP defend,” Puigdemont said.

Prime Minister Mariano Rajoy said his government could not oppose court rulings because it would mean stepping outside the rule of law.