The European Commission is refusing to be precise about the potential EU future of separatist-minded regions, as Flemish nationalists made gains in Belgian local elections and Scotland formally agreed an independence referendum deal.

Rolling back on previously more definite statements about new states being obliged to apply for EU membership, the commission on Monday (15 October) said it would express an opinion only if asked by a member state and only if it concerned a specific situation.

"Concerning certain scenarios, such as the separation of one part of a member state or the creation of a new state, these would not be neutral as regards the EU treaties," said a spokesperson.

The commission would express its opinion on the legal consequences under EU law on request of a member state "detailing a precise scenario."

The new state question has been simmering for some time but has been slowing moving up the political agenda as regionalist and separatist voices in different parts of the EU get louder.

Last month, 1.5 million took to the streets in favour of Catalonia's independence. Capitalising on the growing separatist sentiment, Catalan leader Artur Mas - who wants Catalans to be "allowed to freely and democratically decide their collective future" - has called early elections for 25 November. A win for his party would give him greater clout to negotiate a devolution deal with Madrid.

Things are already further ahead in Scotland. The Scottish National Party won a sweeping victory in the polls last year. On Monday this translated into a deal with London on the terms of a referendum in 2014 on whether Scotland should remain in union with England.

Meanwhile Flemish separatist party N-VA, headed by Bart De Wever, won decisively in Sunday's (14 October) local elections.

Cas Mudde, an expert writing for Extremis, a website analysing extremism in Europe, suggested that the result which saw hard-right Vlaams Belang lose votes to De Wever's party means that "Flemish nationalism is now squarely back in the conservative, but liberal democratic, camp."

This is "more threatening" to the Belgian state, says Mudde, because De Wever's nationalism is now part of mainstream Belgian politics. De Wever, now to be mayor of the important port city Antwerp, has already said he will work for more Flemish autonomy ahead of the 2014 general elections.

But as the question of a new breakaway state asking for membership has moved from the pages of academic journals to something closer to reality, EU officials - lacking guidance from the EU treaty - have moved to wait-and-see mode.

Just last month, the commission was more talkative. President Jose Manuel Barroso, in an interview about Scotland, told the BBC that new states hoping to join the EU would have to apply for membership.

A commission spokesperson then implied that the same would go for Catalonia, in statements that were later qualified to be about "hypothetical" situations.

The new-found reticence reflects the complexities generally and for each region, including whether Scotland would have to join the single currency and whether Belgium would actually exist as a state without Flanders, something De Wever says would not be the case.