Scottish Independence: EC President Jose Manuel Barroso on new states membership
The European Commission President Jose Manuel Barroso has said all new states have to apply to join the EU and must be accepted by existing members.
He was speaking following remarks made by EC spokesman Olivier Bailly who indicated an independent Scotland would not automatically be given entry.
Mr Bailly later clarified the comment, saying he had referred to Catalonia and not directly to Scotland.
A strong independence movement exists in the Spanish region.
On Tuesday, about 1.5 million people took part in Catalonia's independence rally in Barcelona.
It is held annually on 11 September to mark the Siege of Barcelona 300 years ago.
The Scottish government believes that legally an independent Scotland would remain in the EU.
Cabinet minister Keith Brown had earlier told BBC Radio Scotland's Good Morning Scotland programme: "It is simply our position, and it always has been, that Scotland will accede to the EU simply because we take on the same obligations and treaties that we currently have.
"There is no process for countries to secede from the EU, that is an established fact and nobody is saying otherwise."
The clarification from Mr Bailly was prompted following a news conference in Strasbourg in which he was asked about the membership status of a possible independent Catalonia.
He responded by saying: "There are two different steps, there is a secession process under international law and the request for accession to EU member state under the EU treaties. In the meantime, of course, the new treaty is not part of the EU as he has to make request for accession."
However, by Wednesday lunchtime Mr Bailly clarified his remarks by saying that in a "hypothetical scenario" of a "part of an EU member state" wishing to leave that member state then it is "first and foremost an internal matter within that member state".
He added: "There are several theoretical scenarios under international law and it's not for the Commission to speculate on which choices would be retained - and in any case it's not our business."
Mr Bailly insisted that the Catalonia issue he had addressed could not be used as an indication of the commission's general view.
On the BBC's World at One programme, Mr Barroso said he was not going to speculate about possible secessions because it was not his job to do so.
However, he made it clear that in order to join the European Union there was a "procedure" to follow.
Mr Barroso explained: "It is a procedure of international law. A state has to be a democracy first of all and that state has to apply to become a member of the European Union and all the other member states have to give their consent.
"A new state, if it wants to join the European Union, has to apply to become a member of the European Union like any state. In fact I see no country leaving and I see many countries wanting to join."
A spokesman for the Scottish government said that as far as it was concerned the situation remained that an independent Scotland would remain an integral part of the EU, "as it has been for almost four decades, and by definition Scotland already meets all the criteria of EU membership".
He added: "As many legal and constitutional experts have confirmed, Scotland is part of the territory of the European Union and the people of Scotland are citizens of the EU - there is no provision for either of these circumstances to change upon independence, and the rest of the UK will be exactly the same position.
"We will both be successor states, with exactly the same status within the EU."
However, a spokesman for the Better Together campaign, which is in favour of the UK staying together, said the "SNP's assertion that we would be granted automatic entry has proven to be, like so many of their arguments, a baseless assertion".
He added: "How much longer can Scottish ministers refuse to publish the advice that they have been given on this subject? Instead of spending thousands of pounds of public money on keeping things secret, they should be telling us what independence would actually mean.
"Will we be a member of the EU? Will we have to scrap the pound and join the euro? Will we have to introduce border controls across the rest of the UK? These are questions that need to be answered."
A Foreign Office spokesman said: "The Scottish government needs to be clear on the facts of what independence actually means in practice.
"The UK government is undertaking its own detailed research into the benefits of Scotland's place within the UK, including membership of international organisations. These conclusions will be published in due course."