Brussels warned on Monday that the Spanish northeastern region of Catalonia would no longer be an EU member state if it becomes independent from Spain.

The European Commission decided on Monday to indirectly set out its position on the Catalan self-determination debate, after it refused to comment on last weeks’ pro-independence mass protest in Catalonia.

Answering increasing demands from the Catalan government and the Spanish press, a top EU official said that any new independent state would become ‘ a third country’.

‘Scenarios such as the separation of one part of a member state or the creation of a new state, as we have recall on numerous occasions, would not be neutral as regards to the EU treaties. I think what vice-president Almunia said is entirely in line with what I have just said (…) So in other words, an independent state, because of tis independence, would become a third country vis a vis the EU and as of the day of the independence the EU treaties will no longer apply’, said European Commission spokesperson Pia Ahrenkilde Hansen.

The warning came after European Commission vice-president Joaquin Almunia said on Monday that if part of a member state becomes independent, “the segrated part is not an EU member.”. Speaking in the Catalan city of Barcelona, Almunia also expressed the Commission’s concern over the situation in Catalonia and urged the Spanish and Catalan authorities to come to an agreement. The Commission spokesperson said, however, that the EU executive would only lay out an official legal analysis on the situation if a members state requested so.

‘We would only express our opinion on the legal consequences under EU law on request from a member state detailing a precise scenario. Any European state which complies with the principles set out in article 2 of the EU treaty may request membership of the union. So those are the rules. So I think this is what Mr. Almunia was referring to’, said European Commission spokesperson Pia Ahrenkilde Hansen.

Forming a 400 km human chain across the region, over 1.5 million people took to the streets of Catalonia last Wednesday to demand independence from Spain.

Catalonia wants to hold a self-determination referendum next year but the Spanish government strongly opposes the move.