Nicola Sturgeon has said fracking protesters should not be considered “domestic extremists” after police labelling them as such was raised at First Minister’s Questions.

Scottish Green co-convener Patrick Harvie referred to news reports the campaigners against fracking were among those Police Scotland termed “domestic extremists”.

He said: “We’ve known for years that environmental campaigners, along with peace activists and others, have, in the past, been spied on or infiltrated by police forces in the UK, including in Scotland, but this statement of current practice is shocking.

“Anti-fracking protesters who exercised their democratic right to protest are heroes, yet Police Scotland are labelling them as domestic extremists.”

He asked the First Minister to give an assurance that campaigners, including MSPs, planning to attend a protest against nuclear weapons at Faslane on Saturday will not be subject to the same treatment.

She said: “I do not consider people who protest against nuclear weapons, or fracking, or anything else in a peaceful and democratic way to be extremists in any sense and I would not expect anyone to consider them to be extremist.

“Patrick Harvie is absoutely right that peaceful protest is a fundamental part of democracy.”

She said the police would have to answer for operational decisions which they take, adding she would ask the Chief Constable to address the point raised.

Detective Chief Superintendent Gerry McLean said: “Police Scotland supports the public’s right to protest against anything that concerns them, and will facilitate peaceful protests as long as these are conducted within the law.

“The 2017/18 police plan included a reference to issues which were of legitimate concern to the wider public at that time, but which may have been vulnerable to exploitation by people of a more extreme mindset who could undermine peaceful protest and pose a risk to public safety.

“Police Scotland’s position would never be to describe peaceful protesters as domestic extremists.”