The prosecutor and the Mossos d'Esquadra police have launched a joint investigation into who removed the Spanish flag from the Catalan government's headquarters on Friday, after Spain's electoral authority had disqualified Quim Torra as president.

The incident took place at 9 pm, when members of the pro-independence ANC organization entered the building to once again hang from its main balcony the banner in support of the imprisoned Catalan leaders that has potentially cost Torra his job.

Torra, who was found guilty of disobedience for initially failing to remove the banner during the campaign for the April general election, which led the electoral authority to order he be removed from his post, had passed the banner to the head of the ANC.

On Friday evening, soon after the banner had been replaced on the balcony, someone took down the Spanish flag, which was missing for around 15 minutes before it was put back up, with the ANC claiming responsibility.

The prosecutor and the Catalan police will now investigate who was able to enter the government building after 7 pm, when it is closed to the public.

The presidency office insisted that it had given no orders for the flag to be removed, while Torra explained that an investigation is underway to find out who had entered the building and taken the flag down.