Alex Salmond has challenged David Cameron on his decision to veto agreement in the European Union.
The First Minister said the Prime Minister's decision could have implications for the relationship between Scotland, Wales and Northern Ireland and their European neighbours.
He accused Mr Cameron of "blundering into apparently changing the UK's entire relationship with the European Union" without discussion with his coalition colleagues or the devolved administrations.
Mr Salmond has written to the Prime Minister with six "crucial questions" about the veto of a new European treaty and its implications for Scotland.
They include asking what risk assessment, if any, did the UK Government undertake of the impact of its veto decision on investment into Scotland and the UK, and on negotiations affecting key Scottish industries, and what assessment, if any, was made of how Scotland's interests will be affected in the EU "by being represented by a UK government that is excluded from important decision-making meetings".
He also asked why the Scottish Government and other devolved administrations were not consulted in the use of a veto, and asked him to come to an "urgent" meeting of the Joint Ministerial Committee, involving all four of the UK administrations, so that the full implications of the decision can be discussed.
In the letter, Mr Salmond also asked about press reports that Mr Cameron's negotiating stance was based on "big internal problems" that agreeing to the treaty change would present.
The First Minister said: "It is an extraordinary state of affairs that while the Scottish Government and our agencies were working hard to promote Scotland's interests and industries in China, David Cameron was blundering into apparently changing the UK's entire relationship with the European Union - without even discussing it with his own Lib Dem coalition colleagues, never mind the devolved administrations in Edinburgh, Cardiff and Belfast.
"Given that David Cameron took it upon himself to isolate the UK in Europe - from non-euro and the euro members alike - and without a word of consultation, he now needs to answer six key questions about the implications for Scotland of what he has done.
"As the price of playing to his own backbenchers, the Prime Minister now leads a riven administration - with zero credibility in EU negotiations across the range of policy areas where Scotland's interests are crucially affected."