Scottish Government officials have had “initial” talks with Nato, it has been confirmed.
The discussions, said to have involved senior officials from the international body, took place at Nato headquarters in Brussels, Belgium, within the last few weeks.
The Scottish Government would seek to join Nato if there is a Yes vote in next year’s independence referendum.
But the Scottish delegation was reportedly told that no new member would be allowed to join if it had unresolved military or territorial disputes with other countries.
This was said to be a coded warning that the SNP administration’s pledge to remove Trident nuclear submarines from the Faslane base on the Clyde could be an obstacle to Scotland gaining membership.
A Scottish Government spokeswoman said the talks had been “useful” but that it would “not be appropriate to comment further” on details of the discussions at this time.
But Tory leader Ruth Davidson said: “It is no surprise officials were told that shutting down the submarine base at Faslane was incompatible with entry into the alliance.
“Nato’s position is clear new member states must support a nuclear first-strike policy and will not be admitted until all military disputes with other member countries are resolved.
“That includes basing disputes for nuclear submarines.”
Similarly, Scottish Liberal Democrat leader and former Westminster defence spokesman Willie Rennie said: “This revelation undermines the SNP’s case for strong defences for an independent Scotland.
“To be a normal member of an alliance you should expect to comply with its rules, ethos and purpose. If the SNP want to ditch Trident they’d need to ditch Nato too.
“Leaving Nato would leave Scotland without the cornerstone of defence in Europe, potentially exposing us to considerable threats.
A Scottish Government spokeswoman said: “A meeting between officials from the Scottish Government and Nato took place at Nato HQ in Brussels early last month.
“While we can confirm that a useful initial discussion was had, it would not be appropriate to comment further on detail at this stage.
“Consideration to what further contact will be helpful in the future will be made following the publication of the White Paper on independence.”
A spokesman for Deputy First Minister Nicola Sturgeon said: “An independent Scotland’s continued membership of Nato will be in the strategic interests of our neighbours and partners, including the rest of the UK.
“We have made clear that continued membership is contingent on the removal of nuclear weapons from Scotland, and if the people of Scotland vote Yes they will have voted to support a proposition that calls for the removal of Trident at the earliest safe opportunity.”