Scottish independence: Scotland and EU membership
A third European foreign minister has told the BBC an independent Scotland would have to apply for EU membership.
Latvia's Edgars Rinkevics said Scotland would be considered a "new country".
The Baltic state is due to take over the EU presidency shortly after the Scottish independence referendum, in autumn 2014.
SNP ministers say they would seek to negotiate continued membership in the event of a "Yes" vote, without the need for a formal application.
The comments by Mr Rinkevics came after similar remarks by foreign ministers for the Czech Republic and Ireland.
The Latvian foreign minister also raised the possibility that the rest of the UK might not automatically inherit the UK's membership of the EU.
He said the European Commission was "considering" that question and that a "solid legal opinion" was needed.
The UK government has said it was "confident" that independence for Scotland would create one new state rather than two.
The BBC asked all 27 EU member states and Croatia, which joins in July, to comment on how Scottish independence would be handled by EU countries.
Latvia has become the fifth country, including the UK, to suggest Scotland would need to apply for membership of the EU.
Mr Rinkevics, said: "If Scotland clears independence, it is a new country. The procedure of admitting a new member to the EU would have to be followed.
"All the chapters of negotiations have to be opened, duly negotiated and then closed."
He added: "Member states as well as EU institutions currently have more questions than answers on many items.
"But my belief is that, come Scottish independence, we will have to have accession talks with Scotland as a country that applies for membership, rather than have some kind of different formula in this case."
Mr Rinkevics would not speculate on how long the process might take, except to say that an application by Scotland should be a "bit quicker" than that of Iceland or Croatia, because Scotland is already in the EU.
Ms Creighton also said it may be possible to complete the entry process by the Scottish government's target date for independence in March 2016.
In October 2012, Spain's foreign minister, Jose Manuel Garcia-Margallo, said that "Scotland would have to join the queue and ask to be admitted" to the EU.
The Spanish foreign ministry suggested that this remark was still valid.
Three countries - Estonia, Hungary and Slovakia - indicated a need for clarification.
The Estonian foreign ministry said: "We need a binding legal opinion", including on whether or not the rest of the UK might need to apply for membership.
The Hungarian ambassador in London, János Csák acknowledged: "There are different opinions on whether Scotland would inherit membership or refile accession papers.
"We should wait for Brussels. EU institutions should come up with an understanding of what should happen.".
Slovakia's foreign minister, Miroslav Lajcak, had previously said: "There is no clear answer to this. In the end, it is a political decision made by all the member states."
In response to the BBC survey, half the countries - 14 - said they either did not have a position or did not want to express a view at this stage.
A spokesman for the German government said: "We consider the debate on Scottish independence as a domestic affair and therefore don't comment on it."
Poland said it would, "respect the outcome of any arrangement that would be applied", following the referendum in autumn 2014.
The remaining six countries failed to respond or said they were unable to comment at this point.
In 2007, Scotland's deputy first minister, Nicola Sturgeon, told a Scottish Parliament committee that an independent Scotland's membership of the EU would be "automatic".
In a speech in Brussels on Tuesday, the SNP minister said the Scottish government would seek to negotiate continued membership.
Ms Sturgeon said: "On issues like the Euro, Schengen (free area of movement within Europe) and the rebate, our aim would be to retain the prevailing terms.
"The most powerful case for Scotland's continued membership is not based on law or process - but on common sense, reality and mutual self-interest."
A Scottish government spokesman, added: "The Latvian foreign minister said the European Commission legal service is currently looking at both Scotland and the rest of the UK's position in the EU following a "Yes" vote in 2014.
"We consider that it is possible to prepare and publish a 'precise scenario' that will provide the European Commission with the information it needs to consider an independent Scotland's continued EU membership, and we continue to call on the UK government - as existing member state - to join with us in making such a submission."
A spokesman for the UK foreign office said: "In the event of independence, the UK is confident that the remaining UK would be recognised as the continuator state and could continue to exercise the UK's existing international rights and obligations at international organisations such as the EU, NATO and the UN.