The head of Sweden’s security service has warned that his agency is increasingly dealing with the threat posed by fake news and disinformation aswell as the issue of terrorism.

In an interview with the BBC, Anders Thornberg, the head of Sapo, and a 30-year veteran of Swedish security, claimed that fake news and disinformation were increasingly talked-about issues. Although it is sometimes created within Sweden, Mr Thornberg claimed his service had been playing an increasing role when a foreign state was thought to be behind it.

Mr Thornberg gave the example of a fake letter about an arms deal with Ukraine that bore the forced signature of the country’s defence minister.Another instance saw a false story about a former minister creating a group to battle Eurosceptics – it went on to be picked up by both Russian and British media, just days before the UK’s Brexit vote.

Whilst a fake story about Muslims vandalising a church was spread by bots on social media, the accounts were later found to be based out of the country. Mr Thornberg said "If they want to make uncertainty in our country they are doing that".

He also said that Sweden has been the victims of digital espionage and cyber-intrusions from both Russia and China.

Sweden’s MSB - Civil Contingencies Agency, another body under the control of the country’s Ministry of Defence has also been tasked with spotting disinformation. "What we are doing is looking at what information could affect the well-being of our population, the functionality of our society or could affect negatively our fundamental values - freedom of speech, democracy and individual rights" Mikael Tofvesson, MSB's head of global analysis and monitoring.

Mr Thornberg added that a real test of the country’s efforts to fight disinformation will be the national elections later this year, "I think it's important for us as a security service to inform the public about the threat picture, so we have been putting a lot of efforts to do that,", noting that the agency was not active on Twitter. "Our first tweet on Twitter was "We are on Twitter because of security. Follow us because we follow you," he added.

He told the BBC, that as the elections approach, "we know with our knowledge and our experience from before that activities with political violence and threats will increase," adding "It's very important for us to follow this and we are not shy in Sweden - we say that the biggest threat to our security in that perspective is Russia".

Mr Thornberg also spoke on the threat posed by Islamist extremists, particularly those returning from Iraq and Syria. He told the BBC that, a few years ago the service was worried about 200 extremists but now it is monitoring some 3,000 individuals. Speaking of the threat posed by jihadists, Mr Thornberg said “"We have never seen something like this before in my career in the service. We have a new normal”.