Al-Qaeda has released a statement encouraging attacks against French nationals, saying "it is incumbent upon Muslims to separate their heads from their bodies".
The exhortation to violence will cause further alarm across Europe.
On Tuesday Britain warned that a terrorist attack is now highly likely as it raised the official threat assessment to severe in the middle of ISIS assaults around Europe. Hundreds more police officers were posted across the nation to guard its landmarks in response.
France has borne the brunt of the recent uptick in Islamist violence with October seeing attacks in both Nice and Paris. Three people lost their lives in the southern French city while teacher Samuel Paty was beheaded in the capital after showing his pupils Charlie Hebdo cartoons of the Prophet Muhammad.
On Monday a gunman killed four people in Vienna, Austria, on the city’s final night before lockdown. He was a convicted ISIS supporter who was freed from prison last year after attending a deradicalisation course.
The Al-Qaeda statement was released on social media platform Rocket Chat. Last month The National revealed that extremists are increasingly eschewing mainstream social media in favour of the niche platform.
ISIS supporters used Rocket Chat to celebrate the Nice attacks. Researchers at the Counter Extremism Project (CEP) think tank said they had monitored Rocket Chat media pages in the aftermath of the attacks last week and discovered posts showing bodies of the victims, two of whom were partially beheaded
Rocket Chat spokesperson Markus Kirsch told The National that "we regularly aid law enforcement when they contact us to take down [extremist] content.
"Extremist usage goes against our policies and we strictly condemn any such usage of Rocket Chat whatsoever."
Mr Kirsch added that in cases where the platform is run on a private server far from our reach - we have no technical possibility to remove the content, even if we would like to."
