The organisation, a merger of the "Union of Combattants" and splinter group "22 October" says in a press release that attempts for a peaceful solution in their conflict with Paris has failed and that politicians who came to power through regular elections didn't change anything to bring more autonomy to the island.
In a video, filmed on the night of 31st August and 1 September, verified by journalists of the local newspaper Corse Matin, some 30 heavily-armed and masked combattants were shown in front of a table covered with a banner of the Corsica National Liberation Front (FLNC,) a separatist group.
One masked person read a 5 page statement, pointing out that local elections in June resulted in a "nationalist wave" and a 41 percent win for Gilles Simeoni, defeating the candidate of French President Emmanuel Macron's La République en Marche (LReM), but that the central government in Paris is "blind" and "deaf" over the wishes of the Corsican people, while boosting the power of the prefects.
The group is angry about the "increase of colonial politeness visits" and "patronising bureaucratic talk" as if "nothing changed in this little colony".
The group says its 2016 decision to "demilitarise progressively" was influenced by the hightened state of alert caused by the Islamic State inspired terrorist attacks (notably the assault on satirical magazine Charlie Hebdo on 7 January 2015 and against the Bataclan theatre on 13th of November of that year).
But in spite of this, the group points out, no progress leading to greater autonomy was made. "The FLNC will not abandon the struggle as not a single objective for which it was created was reached," the statement says.
The group warns that renewed use of violence is possible.
"We could stick to the idea" of pacifism, but one "should not forget that if [during the Indian war of independence against the UK] there had been 350,000 Hindus and 70,000,000 Britons, it would have been highly unlikely that Gandhi would have won through non-violence."
The statement calls on local politicians who came to power through direct elections not to "sit silently in the luxury of a crushing victory" and says they expect increased "engagement".
They also warn Paris that if "its politics of contempt continue" they will "definitely and with probably more determination than in the past 'take the roads of combat' they 'know so well'".
The statement ends with a message to the French "who think they are at home on Corsican soil," saying "our country is not yet yours - your country will never be ours".
The FLNC was set up in 1976, and together with various other factions intent on Corsican self-rule, staged hundreds of attacks on the island.
They demanded the recognition of the “national rights of the Corsican people”, including citizenship, language and culture, and the abolition of any traces of "French colonialism".
There have been hundreds of attacks in the 40-year struggle during which nine police officers have been killed.
The FLNC has also been accused of carrying out armed robberies and of extortion through so-called revolutionary taxes.
However, the group suffered from internal feuds in the 1990s, a decade when it also staged the assassination of Corsica's prefect Claude Erignac.