NICOLA Sturgeon has said a breakthrough in Brexit talks is "a welcome step forward" but warned that negotiations are set to get "significantly tougher".
Scotland's First Minister renewed calls for Britain to remain in the single market and customs union and for the devolved administrations to be fully involved in the next phase of talks.
Ms Sturgeon had earlier tweeted that the "devil is in the detail" after the European Commission announced "sufficient progress'' had been made to move negotiations on to the next phase.
And she said "a UK government that is able to say that come what may, it will avoid hard borders with Ireland/NI after Brexit can never again tell Scotland that independence would mean a hard border between Scotland and UK".
The DUP, which props up the minority Conservative government, scuppered a deal aimed at resolving the border issue on Monday.
Britain's Prime Minister Theresa May said the fresh deal would guarantee the rights of three million EU citizens in the UK and ensure there would be no hard border between the north and the Republic.
Ms Sturgeon said: "While the Scottish government remains clear that we wish Brexit was not happening and that the UK as a whole was not leaving the European Union, today's proposed agreement is a welcome step forward in the negotiations.
"The next phase will be significantly tougher and it is essential all the UK's governments are now fully involved in the negotiations on the UK's future relationship with the EU – something that has not happened to this point."
The first minister welcomed the guarantee there would be no hard border on the island of Ireland and said the Scottish government would seek clarity on how full alignment with the rules of the single market and customs union would be delivered.
"I am absolutely clear that any special arrangements for Northern Ireland must now be available to other nations of the UK – the Scottish government will not accept any arrangements which risk putting Scotland at an economic disadvantage," she said.
"Short of continuing EU membership, the best outcome for jobs and living standards is to retain membership of the single market and customs union – both in transition and permanently."
Scottish Conservative leader Ruth Davidson said the development was "a real step forward".
"Throughout this process, my overriding priority has been to ensure we act as one United Kingdom and no home nation is left behind.
"I am therefore glad that this morning's agreement ensures the integrity of the UK," she said.
"The work on a comprehensive trade agreement with the EU27 can now begin.
"This will require more hard work and patience. But I am optimistic that Britain and Europe can together build a new relationship, underpinned by the ties of trade, shared values and mutual interest. It is in all our interests."
Ms Davidson criticised Ms Sturgeon for linking the developments to Scottish independence, calling on the SNP leader to "give it a rest".
Labour's shadow Scottish secretary Lesley Laird MP said the news was a "step in the right direction" but careful scrutiny would be needed to shed light on the details of the proposal.
Scottish Liberal Democrat leader Willie Rennie renewed calls for a referendum on the final Brexit deal.
