The leader of the SNP has warned in Brussels of a possible second referendum on Scottish independence if the UK votes to leave the EU.
In her first speech in Brussels as first minister of Scotland Sturgeon said a Brexit from the European Union could be one scenario that "would precipitate popular demand for a second independence referendum".
Speaking at the European Policy Centre Sturgeon warned if Britain were to leave the EU against the will of the Scottish electorate "it would provoke a strong backlash among many ordinary voters".
She added: "Bluntly, I believe the groundswell of anger among ordinary people in Scotland in these circumstances could produce a clamour for another independence referendum, which may well be unstoppable."
The SNP leader broadly outlined the differences between her party's position on the EU and the Conservative government at Westminster.
"We believe that reforms can be implemented within the existing Treaty framework, rather than requiring Treaty change.
"We see the European Union as a positive force in Scotland and in the UK as a whole. And so throughout the coming months and years, we will make an overwhelmingly positive case for Europe," she said.
Chancellor George Osborne has opened informal talks with European nations on how to rewrite the terms of Britain's place in the EU ahead of a proposed referendum on UK membership in 2017.
The Scottish first minister also reiterated Holyrood's commitment to the European Convention on Human Rights (ECHR), calling the it "one of the finest and most important achievements of the post-war era in Europe."
She said: "It defies belief that any government could even consider trying to distance the UK from the Convention. And I want to make it clear today that the Scottish government's belief in European co-operation includes a firm belief in the principles of the ECHR."
Addressing fears that Scotland might not automatically qualify for EU membership if the country became independent, Nicola Sturgeon said because Scotland was a member of a multi-national British state "none of the nations that make up the UK should be at risk of being forced out of the EU against their will."
The SNP leader began her speech with tributes to the late Charles Kennedy. She said the former Liberal Democrat leader and staunch Europhile was "an incredibly talented, gifted, effective politician."